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A comparative Study on the conversion of an energetic H+ beam inside a cell neutralizer filled with hydrogen gas target is conducted by two different methods to determine the maximum beam neutralization efficiency and corresponding optimal gas thickness in terms of beam energy, ranging from 1 keV to 10 MeV. One method analytically solves the equations of particle flux with a deterministic response. The other uses the random collisional probability based on the Monte Carlo simulation with non-deterministic response, which is implemented by COMSOL software. Effective reactions of charge exchange and reionization are commonly considered in both methods with the energy-depended collisional cross section. The results obtained from the two methods are compared, demonstrating good fitness with a mean difference of ±1.5 %. This acceptive difference arises often due to statistical errors that occur in the Monte Carlo calculations. Additionally, a close agreement is found between calculated and measured efficiencies. [Display omitted] • The Monte Carlo simulation agrees with the analytical solution and experiment. • The hydrogen neutralization is influenced by beam energy and gas target thickness. • Increasing the density increases the rate of neutralization, not its maximum value. • Collisional cross section of hydrogen considerably affects the calculational results. [ABSTRACT FROM AUTHOR]

• Electron interactions in DNA material. • Geant4-DNA electron transport in DNA. • Electron stopping power in DNA. • Electron range in DNA. • Ionisation sampling method. In this study we are introducing an update of the Geant4-DNA physics constructor "option 6" including electron interactions with all constituents of the DNA molecule in addition to those already publicly available for liquid water. The new implementation is based on the interaction cross sections of electrons with the four DNA nucleobases, deoxyribose and phosphoric acid for elastic scattering, electronic excitation and ionisation in the 11 eV – 1 MeV energy range. An additional sampling method to estimate the transferred secondary electron energy produced by ionisation is also introduced and can be optionally activated instead of the classical interpolation method based on the differential cross section tables, thus eliminating the need to upload large data files. The implementation in Geant4-DNA was verified by calculating range and electronic stopping power in the various materials. Good agreement is observed with the data available in the literature, and calculations with the interpolation method and the sampling method showed less than 4% difference. No differences were observed in terms of computational cost. [ABSTRACT FROM AUTHOR]

The Murchison meteorite is a well-studied carbonaceous chondrite with relatively high concentrations of amino acids thought to be endogenous to the meteorite, in part because they are characterized by carbon isotope (δ13C) values higher than those typical of terrestrial amino acids. Past studies have proposed that extraterrestrial amino acids in the Murchison meteorite could have formed by Strecker synthesis (for α-amino acids), Michael addition (for β-amino acids), or reductive amination, but a lack of constraints have prevented confident discrimination among these possibilities, or assignment of specific formation pathways to each of several specific amino acids. Position-specific carbon isotope analysis differentiates amongst these mechanisms by relating molecular sites to isotopically distinct carbon sources and by constraining isotope effects associated with elementary chemical reactions. Prior measurements of the position-specific carbon isotopic composition of α-alanine from the Murchison CM chondrite demonstrated that alanine's high δ13C VPDB value is attributable to the amine carbon (δ13C VPDB = +142 ± 20‰), consistent with Strecker synthesis drawing on 13C-rich carbonyl groups in precursors (Chimiak et al., 2021). Here, we measured the δ13C composition of fragment ions generated by electron impact ionization of derivatized ⍺-alanine, β-alanine, and aspartic acid from Murchison via gas chromatography-Fourier transform mass spectrometry. α-Alanine's amine carbon yielded δ13C VPDB = +109 ± 21‰, which is consistent with the previously measured value and with formation from 13C-rich precursors. β-Alanine's amine carbon presents a lower δ13C VPDB = +33 ± 24‰, which supports formation from 13C-rich precursors but potentially via a Michael addition mechanism rather than Strecker synthesis. Aspartic acid's amine carbon has δ13C VPDB = −14 ± 5‰, suggesting synthesis from precursors distinct from those that generated the alanine isomers. These measurements indicate that Murchison amino acids are a mixture of compounds made from different synthesis mechanisms, though some subsets likely drew on the same substrates; this conclusion highlights the complexity of extraterrestrial organic synthesis networks and the potential of emerging methods of isotope ratio analysis to elucidate the details of those networks. [ABSTRACT FROM AUTHOR]

• Low-latitude topside ionosphere mismodelling made by NeQuick. • Improving of the NeQuick topside representation through COSMIC-1 data. • Different topside tests with different values of the NeQuick topside parameters. This paper deals with the well-known mismodelling characterizing the NeQuick topside ionosphere at low latitudes, i.e., the fact that the model keeps the two electron density humps typical of the equatorial ionization anomaly as the altitude increases from the height of the F2-layer electron density peak, without merging them in a single peak above the geomagnetic equator as expected. This is because the NeQuick topside ionosphere modelling strongly depends on several bottomside ionosphere parameters, which causes an essential coupling between the topside and the bottomside that in many cases behave differently. This means that this kind of topside ionosphere modelling may lead to inaccurate results, as it is the maintenance at low latitudes of the electron density double hump structure in the topside as the altitude increases. On the base of some recently published results, this paper analyzes the role played by the three NeQuick scale height parameters H 0 , g and r in the description of the electron density above the F2 layer peak height. The results of this work pave the way for a possible solution of this low-latitude NeQuick topside ionosphere mismodelling. [ABSTRACT FROM AUTHOR]

In this study, the X-ray spectrum smoothing is applied to improve the reading precision of the experimental X-ray peak net counts. The experimental Sn L-shell X-ray production cross sections (XRPCSs) and Bi- M α β XRPCSs before and after smoothing are compared, respectively. The result shows that spectrum smoothing effectively improves the accuracy of the experimental XRPCSs. The after-smoothing present XRPCSs agree well with the distorted wave Born approximation (DWBA) theoretical XRPCSs and are consistent with the previously published XRPCSs within the experimental uncertainty. Finally, the factors affecting the comparison between the experimental and DWBA theoretical XRPCSs are analyzed. [ABSTRACT FROM AUTHOR]

The electron-impact widths for 13 Si II multiplets, belonging to the 3s3p( 3 P o )nl configuration, have been calculated by using the modified semiempirical method. Since a number of these lines is in visible, they are of interest and for analysis and synthesis of stellar Si II lines, abundance determination and modelling of stellar atmospheres.The obtained results have been compared with available experimental and theoretical data and used for the investigation of regularities within supermultiplets. [ABSTRACT FROM AUTHOR]

[Display omitted] • The method is specific and precise for Epichlorohydrin, 1,6-Dibromohexane and 1-Bromodecane. • Evaluated for genotoxic impurities in Colesevelam hydrochloride. • The analytes were quantified by GC-EI-MS with SIM. A selectivity-based gas chromatography coupled with a mass detector (GC–MS) technique was developed and evaluated to detect genotoxic impurities in the "Colesevelam hydrochloride (COLH)" drug substance. A chromatographic separation was performed using an HP-5MS column of 30 m long, 0.32 mm in diameter and 1.0 µm thick. For the determination of Epichlorohydrin, 1,6-Dibromohexane and 1-Bromodecane contents, the mass fragments (m / z) 57, 83 and 135 were selected as quantification ions and the mass fragments (m / z) 49, 55 and 57 were selected as qualifier ions respectively. These compounds are analysed using gas chromatography coupled with electron ionization mass spectrometry (GC-EI-MS) using selective ion monitoring (SIM). This method is specific, sensitive, linear, accurate, precise and robust. The respective limits of detection (LOD) and limits of quantification (LOQ) values for Epichlorohydrin, 1,6-Dibromohexane, and 1-Bromodecane were 0.03 µg/g and 0.10 µg/g, 0.03 µg/g and 0.10 µg/g, and 0.03 µg/g and 0.10 µg/g, respectively. The correlation co-efficient value of the linearity experiment was 0.9995 for Epichlorohydrin, 0.9997 for 1,6-Dibromohexane and 0.9997 for 1-Bromodecane. The average recovery for Epichlorohydrin was 97.0 %, 1,6-Dibromohexane 103.4 % and for 1-Bromodecane was 106.3 %. The present method is precise according to system, method and intermediate precision. These results demonstrate that controlling for Epichlorohydrin, 1,6-Dibromohexane, and 1-Bromodecane in COLH drug substance is both straightforward and economical. [ABSTRACT FROM AUTHOR]

The wavelength dependence of the holographic interference structure in the photoelectron momentum distribution (PMD) of hydrogen atoms under a few-cycle chirped laser field is investigated using a two-dimensional (2D) semiclassical two-step (SCTS) model. Under the constraint of a fixed chirp parameter, we observe an amplification in the impact of the chirp parameter on the laser field waveform as the wavelength increases. This enhancement facilitates effective modulation of the ionization time window. As the wavelength reaches a certain threshold, the double-slit interference pattern undergoes an observable expansion towards the left. Furthermore, based on the variations in X-axis momentum (P x) concerning ionization time at different wavelengths and the corresponding distribution of classical electron trajectories at those wavelengths, we present a more comprehensive explanation for the expansion of interference patterns. This expansion can be attributed to changes in wavelength, which result in modifications to the laser field's waveform, consequently leading to a significant acceleration of ionized electrons when exposed to chirped laser pulses. It is worth noting that by tuning the negative chirp parameter, the leftward expansion of the double-slit interference pattern can also be achieved, particularly when shorter wavelengths of chirped laser pulses are employed. • QTMC method was used to calculate the photoelectron momentum distribution of hydrogen atoms in a chirped laser field. • We adjust the wavelength of the chirped laser field to obtain different photoelectron momentum distributions. • The trajectories of electron ionization are analyzed under classical calculations. [ABSTRACT FROM AUTHOR]

• The single use commercial material was converted to reusable material with recyclability of more than 5 cycles. • The magnetic SPE based method was found very simple, precise and rapid. • The method showed good reproducibility and recovery in tap and formation water samples containing chemical tracers i.e, Fluorobenzoic acids. • The simulation study was performed using material studio to determine the adsorption sites of the material. • The analytical greenness was determined by AGREE software which proved the method more greener than the existing methods. The present study describes the trace analysis of 23 fluorinated aromatic carboxylic acids based on the dispersive magnetic solid phase extraction (m-SPE) technique coupled with the gas chromatography coupled with mass spectrometry (GC–MS) electron ionization (EI) technique. A commercial hydrophilic-lipophilic balanced (HLB) material polystyrene divinyl benzene having urea functional groups was modified with magnetite nanoparticles and employed as a sorbent for dispersive m-SPE of fluorobenzoic acids (FBAs) from the tap and formation water samples. The extraction occurred due to π- π interaction between the aromatic ring of synthesized sorbent and the aromatic ring of FBAs, the hydrogen bond formation between the urea functional group of the sorbent and carbonyl oxygen, fluorine of the FBAs. As a result, the method was precise, rapid, reproducible, and calibrated with the coefficient of variation (R2) greater than 0.98 for all 23 compounds. The instrument detection limit (IDL) and method detection limit (MDL) were found in the range of 2.60 – 8.25 ng/mL and 0.08 – 0.28 ng/mL respectively. Extraction efficiencies were found in the range of 83.80–100 % for tap water samples and 78.41–98.92 % for formation water samples, respectively, with an enrichment factor of 33.33–66.66 and a maximum RSD of 7.07 %. The recyclability and magnetic properties of the synthesized material were also investigated, resulting in the material being reused for six cycles without impacting its performance; hence, the method offers rapid determination and high throughput analysis of FBAs. In addition, simulation studies were performed using the adsorption location tool of Material Studio, confirming the interaction sites of sorbent with FBAs. AGREE evaluated the analytical greenness of the method, and the score was found to be 0.51. [ABSTRACT FROM AUTHOR]

This study deals with the evaluation of moment-curvature response and curvature ductility of reinforced ultra high performance concrete (R-UHPC) cross-sections. Curvature ductility is calculated based on six definitions. The impact of these definitions is demonstrated through the calculation of strength reduction factors and comparisons of factored flexural strength of R-UHPC and reinforced normal strength concrete (R-NSC) cross-sections. Strategies for improving the curvature ductility of R-UHPC cross-sections are presented. A versatile framework to predict the complete moment curvature response of R-UHPC cross-sections is proposed. The proposed procedure is used to study the effect of tension reinforcement ratio, UHPC strain at crack localization, UHPC tension model, UHPC ultimate tensile strain, and compression reinforcement ratio on curvature ductility and complete moment curvature response. It is determined that for a given cross-section, changing the material from NSC to UHPC causes notable reductions in curvature ductility. This reduction applies to: 1) tension and compression reinforcement ratios that range from 0.69–2.78 % and 0 – 1.37 %, respectively; 2) UHPC tension models that feature elasto-plastic and linear strain hardening responses with and without residual branches; and 3) UHPC ultimate tensile strains that range from 0.005–0.015. Such reductions in curvature ductility render the considered R-UHPC cross-sections as members in the transition zone – a classification currently prohibited for R-NSC sections according to ACI 318–19 (22) - while their R-NSC counterparts qualify as tension-controlled. This results in lower strength reduction factors for R-UHPC cross-sections and limits the benefits of UHPC when flexural strength controls design. It is concluded that R-UHPC cross-sections that feature either the highest or the lowest reinforcement ratios provide the highest added benefit from the point of view of enhancing factored flexural strength compared to R-NSC sections. The most effective method to elevate curvature ductility is an increase in the UHPC strain at crack localization. A minimum UHPC strain at crack localization of 0.006 is required to change the classification of cross-sections from the transition zone to tension-controlled. The use of compression reinforcement - an established technique for R-NSC members to induce a change in the flexural failure mode by elevating curvature ductility - was determined to have almost no influence on the curvature ductility of R-UHPC cross-sections. • A procedure is presented to obtain the complete M − χ response of R-UHPC cross-sections. • The impact of several parameters on M − χ response and curvature ductility is examined. • R-UHPC sections exhibit much lower curvature ductility than R-NSC counterparts. • None of the considered R-UHPC sections qualifies as a tensioned controlled section. • Strategies for increasing curvature ductility of R-UHPC sections are presented. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dielectric barrier discharge ionization (DBDI) is applied to fluoroalkyl substances. • Fluorotelomer alcohols and acrylates are detected by DBDI with characteristic ions. • Signals obtained by DBDI are compared to electron ionization. • Structure of ions and fragments is confirmed with stable isotope-labelled material. • Six fluorotelomer alcohols and acrylates are separated by gas chromatography. Fluorotelomer alcohols (FTOHs) and acrylates (FTACs) have been reported as precursors of perfluoroalkyl acids and are known to contaminate biotic and abiotic compartments. Here, a detailed study was carried out for assessing the capability of dielectric barrier discharge ionization (DBDI) to be used as soft ionization technique, as alternative to the more energetic electron ionization (EI), for the quantitative determination of four FTOHs and two FTACs in environmental, biological or food samples by gas chromatography-mass spectrometry. While gas chromatography-EI-mass spectrometry (GC-EI-MS) shows significant fragmentation of the compounds, the ionization obtained by gas chromatography-DBDI-high resolution mass spectrometry (GC-DBDI-HRMS) affords dominant molecular adducts on the spectra. In the positive ion mode, the ion [M + H 3 O]+ and, of lower intensity, [M + H]+ are observed in the spectra of FTOHs, while the ion [M + H]+ is the most abundant in the spectra of FTACs and accompanied by a lower signal attributed to the ion [M + NO]+. In the negative ion mode, the FTOHs give rise to carbon dioxide and oxygen adducts observed with ions [M − H + CO 2 ]- and [M + O 2 ]-. Structure assignments were confirmed with stable isotope-labelled FTOH analogs and 13CO 2. Gas chromatographic separation of the six compounds reveals room for development of methods applicable to soils, plants, water, food and biological materials. [ABSTRACT FROM AUTHOR]

This work experimentally and numerically studied the kinetic roles of non-equilibrium nanosecond pulsed discharge in the oxidation and ignition of NH 3 /O 2 /Ar mixture at low temperatures. Electron ionization molecular beam mass spectrometry (EI-MBMS) was used to qualify and quantify the species pool in NH 3 /O 2 /Ar plasma, involving NH 3 , O 2 , H 2 O, N 2 , NO, and N 2 O. A complete set of electron scattering cross sections of NH 3 , including elastic, rotational, vibrational excitation, electronic excitation, dissociation, and ionization, calculated via the R -matrix method was included in the developed plasma assisted NH 3 /O 2 /Ar oxidation kinetic mechanism. Rate constants of reactions involving vibrational and electronic excited ammonia, NH 3 (v) and NH 3 (e), were calculated with the Fridman-Macheret α -model and Modified Method of Vibronic Terms (MMVT), respectively. The corresponding rate constants were expressed in the Arrhenius equation and featured decreased active energy barriers or increased pre-exponential factors compared to the reactions involving ground state NH 3. Key reactions that activated NH 3 consumption, e + NH 3 → e + NH 3 (e), and NH 3 (e) + X → NH 2 + XH were included based on the newly-calculated cross sections. The concentrations of reactants and main products predicted by the proposed model were consistent with the experimental measurements in the wide range of inlet O 2 mole fractions and applied voltages. Model analysis revealed that the electron impact reactions and plasma reactions involved excited species such as O(1D), Ar⁎, and electrons played key roles in the initial oxidation of NH 3. A non-monotonic relationship between ignition delay time and O 2 mole fractions was observed in the low-temperature plasma assisted NH 3 ignition due to the competitive reaction channels between O(1D) reactions with NH 3 and O 2. This work provided kinetic insight into low-temperature plasma assisted NH 3 oxidation and ignition for future engine applications. [ABSTRACT FROM AUTHOR]

Controlling the quantum interference in nanoscaled systems has potential application for the realization of high-performance functional devices. In this work, the quantum interference of a T-shaped double-quantum-dot system is studied in detail by evaluation of differential conductance by means of nonequilibrium Green's function method. The factors of Coulomb interaction in Luttinger liquid leads, electron–phonon interaction, interdot tunneling, and dot-lead coupling are taken into account. In the differential conductance curve, there appear a series of antiresonance dips due to phonon-assisted destructive interference when the interdot tunneling is weak, and they can coexist with zero-bias antiresonance dip. When the dot-lead couplings are asymmetric, both the antiresonance dip and Fano line shape dip can occur for strong dot-lead coupling. Our results also show the coexistence of low-bias negative differential conductance and Fano antiresonance, as a manifestation of the interplay between strong intralead Coulomb interaction and weak dot-lead coupling. These interference phenomena emerged in a relatively simple model promises helpful guidance for controlling over the electrical performance of interference-based molecular devices. • Manipulating quantum interference in T-shaped coupled vibrating moleculars is explored. • The effect of intralead Coulomb and electron–phonon interactions on interference is studied. • There appeared sets of antiresonance dips due to phonon-assisted destructive interference. • The coexistence of zero-bias antiresonance dip and Fano line shape dip occurs for dot-lead asymmetric coupling. • There shows the coexistence of low-bias negative differential conductance and Fano antiresonance. [ABSTRACT FROM AUTHOR]

Laser desorption mass spectrometry was employed to study rubrene using three different sample preparation methods. Pressed-pellet and films drop-cast from solution were investigated with a laser-desorption time-of-flight spectrometer. Jet-cooled rubrene cations were produced in a supersonic molecular beam by laser desorption from a film-coated metal rod and detected with time-of-flight mass spectrometry. The films for this process were produced by vacuum sublimation of powder samples. The mass spectra from each of these samples contained the parent molecular ion and fragments resulting from phenyl ring elimination - a pattern similar to that produced by electron impact ionization. The amount of fragmentation varied with sample preparation and desorption laser wavelength. The rubrene cation was mass selected and studied with UV laser photodissociation at 355 nm. The resulting fragmentation mass spectrum indicated the loss of one or two phenyl groups, but no more than this. Computational studies of the ion energetics were used to investigate the stable fragment ion structures and understand the energetics of the dissociation process. [Display omitted] • Laser desorption mass spectrometry studied for rubrene at 532 and 355 nm. • Strong wavelength dependence for LD-ToF. • Photodissociation of mass-selected rubrene cation at 355 nm. • Computational studies of fragmentation energetics. • Elimination of biphenyl as dominant photochemical path. [ABSTRACT FROM AUTHOR]

• K X-ray production cross by impact of 12C and 13C ions were measured. • This is the first time that 13C ions are used to induce K X-rays of transition metals. • An isotopic effect is observed. • The cross sections measured for 13C are lower than those for 12C at the same energies. • The cross sections are similar for equal velocity ions. K X-ray production cross sections of Co, Ni, and Zn due to the impact of 2.48 MeV to 3.84 MeV 12C3+ and 13C3+ ions were experimentally determined using the thick target approach. It was possible to observe differences in the cross sections due to the distinct mass of the ions. A reduced variable v 1 / v 2K , where v 1 is the ion velocity and v 2K is the (Bohr) electron orbital velocity, was considered to scale the ion energies. When the data were plotted as a function of the reduced variable, a single curve was obtained for all targets and both isotopes. Comparisons with several models were also made, including corrections due to electron capture and multiple ionization. It was found that the adiabatic perturbation with molecular orbitals formation, plus electron capture and multiple ionization corrections, is the theory that better describes the experimental results. [ABSTRACT FROM AUTHOR]

Inner-shell ionization has many applications related to material analysis. However, full theoretical calculations in heavy multielectronic atoms are scarce. In this contribution, we assess proton and electron impact L i and M i -subshell ionization cross-sections of heavy targets (72 ≤ Z ≤ 83) using two theoretical models. These calculations are based on the Distorted Plane Wave Born Approximation for electron impact and the shellwise local plasma approximation for the proton impact, combined with relativistic calculations of these deep subshells wave functions and binding energies. We analyze the L-shell ionization of W, Au, and Bi and the M-shell of Hf, Ta, W, Re, Os, Pt, Au, Pb, and Bi. Present values are compared with available experimental data from the literature, with disparate agreement. The convergence of proton and electron impact cross-sections at high-impact velocities is also discussed. [ABSTRACT FROM AUTHOR]

Our Δ E − E telescope elastic recoil detection analysis (ERDA) system employed a gas ionization chamber (GIC), which consisted of a U-shaped cathode, Frisch grid, and anode. The cathode shape was designed to downsize the electrodes. The difference of performance between the U-shaped and planar shaped cathodes, however, has not been studied well, yet. Therefore, we quantitatively evaluated the influence using the U-shaped cathode on Δ E − E telescope ERDA. The performances of U-shaped and planar shaped cathodes were compared from the viewpoint of a recoil counting loss due to the stagnation inducing a recombination of ion–electron pairs, and the electron uptake by the Frisch grid. No significant difference occurs between the two cathodes from the viewpoint of O recoil yields. The inhomogeneous electric field formed by the U-shaped cathode, however, induced the electron collection suppression, which leads to an attenuation of Δ E pulse heights. In our ERDA condition, the lateral straggling of recoils is suppressed due to their high energy, so that the attenuation of Δ E pulse heights is not severe and does not impair the reliability of Δ E − E telescope ERDA. These results show that the U-shaped cathode can also be used safely for Δ E − E telescope ERDA, and that GICs have a flexibility in the electrode shape, which is useful to make GICs more compact. [ABSTRACT FROM AUTHOR]

Equilibrium charge-state fractions F q and average charges 〈 q 〉 are calculated for ion beams of superheavy Fl q + , Mc q + , Lv q + and Ts q + ions with charges q = 0 – 11 colliding with He atoms at ion energies E = 0.25 – 300 keV/u. The data are obtained using electron-loss and capture cross sections, calculated for He-gas pressures P = 0 and P = 0. 8 mbar with account for the target-density effect. At energies E ≈ 0.25 – 10 keV/u, the influence of the effect is found small, but at higher energies E ≥ 10 keV/u, it becomes important and leads to increase of 〈 q 〉 values by 3 – 5 times. Calculated average charges are in a good agreement with experimental data and semi-empirical estimates available at E = 132 keV/u and P = 0. 8 mbar. The 〈 q 〉 values are also compared with experimental data and other calculations for heavy and superheavy ions with atomic numbers Z = 38 – 114 as a function of the Bohr scaling parameter v Z 1 / 3 , where v is the ion velocity. • Calculations of atomic average charges need an account of the target-density effect. • Average charges of superheavy elements are well scaled with Bohr parameter v Z 1 / 3 . • The density effect shifts the equilibrium fractions towards higher ion charges. [ABSTRACT FROM AUTHOR]

This article reports the electron scattering ionization cross sections for S 2 , S 3 , S 4 , S 5 , S 6 , S 7 , and S 8 target molecules essential to many fields like radiation chemistry, atmospheric, astrophysical, and astrochemical modeling. The theoretical approach utilizes a complex scattering potential ionization contribution method. The computation is carried from the ionization threshold of the target molecule to 5000 eV to investigate the entire energy range, which is significant to the ionization process of the molecules. A simple additivity rule is applied to study complex and non-spherical cases. Further, screening correction is implemented within the molecular system to reduce the overestimation in cross section values due to the overlapping charge density. A high correlation was obtained for the maximum ionization cross section value and the square root of the ratio of polarizability to the target molecule's ionization energy, indicating the present method's accuracy. Besides the Astro modeling applications, the cross section values also find utility in industrial plasma, sulfur lamps, lithium-sulfur batteries, and mass spectrometry. [Display omitted] • Electron interaction with sulfur clusters studied by quantum mechanical formalism. • EPS method helps to identify molecular charge density distribution. • Simple additivity applied to charge density and screening correction applied to refine CS. • Ionization data for S 4 to S 8 target molecules reported for the first time. • Correlation of maximum ionization CS with target parameters observed for clusters. [ABSTRACT FROM AUTHOR]

The TULIP project aims to produce radioactive ion beams of short-lived neutron-deficient isotopes by using fusion-evaporation reactions in an optimized Target Ion Source System (TISS). The first step consisted of the design of a TISS to produce rubidium isotopes. It was tested with a primary beam of 22Ne@4.5 MeV/A irradiating a natural Ni target at the SPIRAL1/GANIL facility in March 2022. Rates of 76 , 78 Rb were measured as well as an exceptionally short atom-to-ion transformation time for an ISOL system, of the order of 200 μ s. The second step of the project aims at producing neutron-deficient short-lived metallic isotopes in the region of 100Sn. A "cold" prototype has been realized to study the electron impact ionization in the TISS cavity and a "hot" version is under construction to prepare an on-line experiment expected in the near future. [ABSTRACT FROM AUTHOR]

A library of hydrazinyl thiazole-linked indenoquinoxaline hybrids 1 – 36 were synthesized via a multistep reaction scheme. All synthesized compounds were characterized by various spectroscopic techniques including EI-MS (electron ionization mass spectrometry) and 1H NMR (nuclear magnetic resonance spectroscopy). Compounds 1 – 36 were evaluated for their inhibitory potential against α -amylase, and α -glucosidase enzymes. Among thirty-six, compounds 2 , 9 , 10 , 13 , 15 , 17 , 21 , 22 , 31 , and 36 showed excellent inhibition against α -amylase (IC 50 = 0.3–76.6 μM) and α -glucosidase (IC 50 = 1.1–92.2 μM). Results were compared to the standard acarbose (IC 50 = 13.5 ± 0.2 μM). All compounds were also evaluated for their DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and compounds 2 , 9 , 10 , 17 , 21 , 31 , and 36 showed (SC 50 = 7.58–125.86 μM) as compared to the standard ascorbic acid (SC 50 = 21.50 ± 0.18 μM). Among this library, compounds 9 and 10 with a hydroxy group on the phenyl rings and thiosemicarbazide bearing intermediate 21 were identified as the most potent inhibitors against α -amylase, and α -glucosidase enzymes. The remaining compounds were found to be moderately active. The molecular docking studies were conducted to understand the binding mode of active inhibitors and kinetic studies of the active compounds followed competitive modes of inhibition. [Display omitted] [ABSTRACT FROM AUTHOR]

The generation of collision-induced vacancies and their transfer within the electronic inner shells are the source of several unprecedented phenomena, which have been revealed in recent experimental studies conducted using state-of-the-art next-generation accelerators and detectors. Despite the multitude of studies conducted over the years, our understanding of the atomic vacancy transfer mechanisms remains exiguous. The detection and analysis of collision-induced X-rays is a widely-used powerful technique for analysing atomic-scale phenomena. However, both experimental and theoretical investigations on ion–atom collision-induced X-rays have remained mostly restricted to high-energy light-ion impact on heavy atoms. To date, only a few studies have been reported on the investigation of very-low-energy heavy-ion impact on heavy atoms using X-rays, especially M-shell X-rays of the heavy atom. This study was conducted to evaluate the inner-shell ionisation of Au (135 and 508 μ g / cm 2 ) and Pb (107, 157 and 390 μ g / cm 2 ) targets due to low-energy (2–5 MeV) 54 Xe q + -ion impact. The collision-induced X-ray spectra of both the collision partners were examined, and the corresponding intensity ratios and cross-sections were compared with those calculated using two well-known ionisation theories, viz. PWBA and ECPSSR. The measured cross-sections were underestimated by these theories. Moreover, the cross-sections measured in this study were found to be several orders of magnitude higher than those obtained in other reported studies on low-energy lighter-ion-impact on Au and Pb. The significant discrepancies observed between the experimental and theoretical values have been explained qualitatively within the framework of quasi-molecular orbital formation using level correlations. The insights obtained from the results of this study can be applied to analyse the vacancy transfer mechanisms in very-heavy systems (combined atomic number > 100). • 2–5 MeV Xe-ions bombarded on foils of Au and Pb with different thicknesses. • Target energy shift, intensity ratios and M-shell production cross-sections investigated. • Discrepancy observed between measured and theoretical (PWBA and ECPSSR) results. • Measured values higher than those reported by other authors. • Cross-section enhancements qualitatively explained using level correlations. [ABSTRACT FROM AUTHOR]

• Metastable Kr atoms are generated by "excitation + radiation" and "ion-electron recombination" processes. • Multiphoton excitation and electron impact excitation dominate the "excitation + radiation" process. • Avalanche ionization dominates the "ion-electron recombination" process. • Energy pooling and photoionization cause the reionization process after laser excited metastable Kr atoms. Preparation of metastable Kr atoms in the 5s[3/2] 2 level via laser-induced ionization has been achieved. The temporal evolution of the intensity of Kr atomic spectral lines at 760.15 nm, 811.29 nm, and 431.96 nm was used to elucidate the production mechanisms of metastable Kr atoms. These mechanisms primarily involve two processes: the "excitation + radiation" process, dominated by multiphoton excitation and initial plasma-induced electron impact excitation, and the "ion-electron recombination" process, governed by avalanche ionization. The decay time constants of Kr atomic spectral lines, corresponding to the "excitation + radiation" and "ion-electron recombination" processes respectively, were obtained experimentally under both strong and weak ionization conditions. The experiments revealed delay in preparations of metastable Kr atoms between these two processes. To reduce the loss of metastable Kr atoms and effectively utilize their peak concentration, we drew inspiration from metastable rare gas lasers and proposed the "cycling" idea to keep metastable Kr atoms produced by these two processes as synchronized as possible. We used 811.29 nm laser to excite metastable Kr atoms generated rapidly during the "excitation + radiation" stage to the 5p[5/2] 3 level. The Kr atoms returned to the 5s[3/2] 2 level through spontaneous radiation, merging with metastable Kr atoms that were slowly produced during the "ion-electron recombination" stage. We hope that the "cycling" idea can shorten the delay in preparations of metastable Kr atoms from both processes and enhance the peak concentration of metastable Kr atoms. However, the experimental results didn't meet expectations, as we observed a decrease in the 811.29 nm fluorescence after laser excitation, attributed to the accumulation of 5p[5/2] 3 level Kr atoms. These atoms undergo energy pooling to populate the 4d'[3/2] 1 and 5d[7/2] 3 levels, followed by absorption of 811.29 nm laser energy leading to photoionization. Reducing the concentration of 5p[5/2] 3 level Kr atoms helps mitigate the reionization issue. [ABSTRACT FROM AUTHOR]

The adoption of Heavy Ion PIXE for elemental quantification remains limited by the lack of fundamental atomic parameters needed for the calculation of X-ray production cross section data. Widely adapted theoretical models used for approximating ionisation cross sections, as well as other atomic physical parameters such as X-ray fluorescence yields, are calculated based on single-hole vacancy production post ion-atom impact. This renders the use of conventional 'protonic' models invalid for heavy ion-atom collisions. The degree to which Multiple Ionisation (MI) manifests in different heavy ion-atom collision symmetries significantly modifies atomic physical parameters. This is due to the significant number of introduced spectator vacancies in higher subshells, especially where near-symmetry is approached and MI is more pronounced. Knowledge of the mean number of vacancies in upper subshells is thus important for modifying atomic parameters that are needed for the translation of ionisation to X-ray production cross sections. In the present study, MI effects for Sn L-shell X-rays were studied using characteristic X-ray energy shifts measured using a standard PIXE spectrometer induced by Si, Cu and I projectile ions with incident energies up to 0.75 MeV/u. MI satellite distributions were studied using a Wavelength dispersive X-ray spectrometer (WDS) for high resolution PIXE, induced by C and Si projectile ions with incident ion energies up to 1.25 MeV/u. The mean number of subshell vacancies in the M- and N- shell for energy shifted Sn Lα X-ray lines were determined using both standard and high resolution PIXE spectrometers. • Experimental mean shell vacancies due to C, Si, Cu and I incident ions with energies up to 1.25 MeV/u measured. • ECPSSR predictions underestimate experimental data for near symmetric I–Sn collisions by less than 3% below 23 MeV. • Mean subshell vacancies immeasurable for small X-ray energy shifts measured using an SDD. [ABSTRACT FROM AUTHOR]

• The calculation method of ground synthetic field intensity at different altitudes is presented. With the increase in altitude, the ground synthetic field strength gradually increases, leading to a corresponding increase in the relative voltage between the human body and the metal greenhouse under the power line. • A transient electric shock dynamic simulation method that takes into account altitude is proposed in this study. The formula for electron ionization and adhesion coefficient, which varies with altitude, is obtained through fitting. It is found that under the same contact gap distance, the electric field intensity and streamer radius of the discharge gap increase with higher altitudes. Additionally, the average streamer speed also significantly increases at higher altitudes, resulting in a faster shock to the human body. • The higher the altitude, the greater the transient electric shock current that flows through the human body via the metal greenhouse and the contact gap beneath the UHVDC transmission line. This results in a larger amount of transient electric shock energy being received by the human body, leading to a stronger sensation of electric shock and causing serious pain. However, it is important to note that this level of pain is still far from causing death to the human body. Aiming at the issue that existing research methods for human transient electric shock do not take into account the altitude factor, resulting in deviations in transient electric shock calculations at high altitudes, a dynamic simulation method of the electric shock process considering actual environmental factors is proposed. The study investigates the characteristics of line-induced voltage at different altitudes. Based on this, a dynamic model of the electric shock process is established and the formula for model parameters is fitted with altitude. This allows for analysis of streamer propagation characteristics and transient electric shock current at different altitudes. The effectiveness of this method is verified by comparing it to existing experiments. Finally, an evaluation of human transient electric shock at different altitudes is conducted. Previous studies have identified metal greenhouses as the primary sites of transient electric shock phenomena under UHVDC lines, and these structures have been utilized as the focus of research. The research reveals that as altitude increases, there is an increase in relative voltage between the human body and metal greenhouse, reaching 3261.3 V at an altitude of 4000 m; however, this relative voltage growth decreases with higher altitudes. The electron ionization coefficient increases rapidly while the adhesion coefficient increases slowly with elevation. Under a constant contact gap distance, there is faster reception of electric shock by the human body with increasing altitude. Additionally, there is a larger amount of transient electric shock energy received by the human body; its maximum value being 5.358 mJ - although this is far less than the human death threshold of 25 J and will not cause death to humans. [ABSTRACT FROM AUTHOR]

This manuscript is devoted to explore the atomic structure and electron impact excitation process of atom impurities in quantum dots. To achieve this goal, a method that solves the fully relativistic Dirac equation within the framework of relativistic configuration interaction is proposed. The Gaussian potential is used, which can accurately describe the location of impurities in quantum dots and their local effects on the surrounding electron cloud. The coupled Dirac equation is modified to include a new central potential, providing solutions that include both the continuous and bound state wave functions. The process of electron impact excitation is elucidated using the distorted wave method, all within the framework of relativistic Dirac theory. For illustrative purposes, a detailed investigation of the excitation energies, transition rates, wave functions, and excitation cross sections is carried out for a wide range of confinement strengths of the potential and quantum dot radii, using the helium impurities in spherical quantum dots as an example. Our results reveal that for a given confinement strength of the potential, the bound state wave functions are initially pulled into the inner region by the attractive Gaussian potential well, but eventually reflect the free atom scenario at large quantum dot radii. In contrast, the continuous electron wave functions exhibit monotonic variations as a function of the quantum dot radii. Such behavior of the wave functions gives rise to distinctive phenomena in the variation of excitation energies, transition rates, and excitation cross sections in relation to the potential parameters. Good agreement between the present results and existing data, where available, is obtained. This work holds importance not only for basic research in atomic physics but also for the optical and electronic applications of quantum dots. I.e., in the design and optimization of quantum dot lasers and quantum dot sensors. • The electronic structure and electron impact excitation process of helium impurities in quantum dots are studied. • The fully relativistic method combined with a Gaussian potential is proposed. • This work is important in the areas of atomic physics and optics. [ABSTRACT FROM AUTHOR]

Mass spectrometers have gained increasing importance in recent space missions. This paper presents the development of a miniature Mattauch-Herzog mass spectrometer for mass analysis. The mass spectrometer consists of an electron ionization (EI) source, an electrostatic and magnetic mass analyzer, and a focal plane detector. The construction of the EI source is based on a study of the impact of electrode voltages on ion focusing performance and ion transmission efficiency using the phase space method in the SIMION-8.1 software. The SIMION model of the mass analyzer is utilized to analyze the effects of electrostatic field voltage and magnetic fringe field on the ion beam. Experimental results from the instrument prototype demonstrate that the ion beam is influenced by the electrostatic field in a manner consistent with the simulation results of the SIMION model. The theoretical mass-to-charge ratio range of this double focusing mass spectrometer (DFMS) is 8amu–300amu, and it is capable of distinguishing isotopes with mass differences larger than 0.3amu, such as Ne. The N 2 peak width at Full Width Half Maximum (FWHM) is 0.4amu, the mass resolution is 70.0, and the minimum detectable pressure of N 2 is 2.8 × 10−9Pa. The Xe peak width (FWHM) is 1.3amu, the mass resolution is 101.5, and the minimum detectable pressure of Xe is 4.4 × 10−9Pa. • Miniaturized design of Mattauch-Herzog mass spectrometer. • The study of the electrostatic and magnetic fringe field effect and optimization design. • The performance indicators research for DFMS, including the isotope detection. [ABSTRACT FROM AUTHOR]

• Synthetic ester insulating oil is a dielectric liquid with balanced properties. • A strategy to improve the lightning breakdown characteristics based on the design of molecular chain length. • Revealing the correlation between microscopic electron structural parameters and macroscopic discharge behavior. The high flash point and biodegradability of synthetic ester insulating oil offer transformers both operational stability and environmental protection. However, its poor lightning breakdown characteristics under long oil gaps and inhomogeneous electric field often lead to rapid streamer discharges, posing challenges and limits to the use of synthetic ester insulating oil and hinders the development of low-carbon, eco-friendly high voltage power transformers. To address this issue, we propose improving the lightning breakdown characteristics through molecular chain length design. Using density functional theory, time-dependent density functional theory, and wave function analysis, we investigate how microscopic factors like molecular polarity, discharge active sites, frontier orbitals, traps, ionization and electron affinity, and excitation processes influence macroscopic discharge characteristics. Our findings show that under an electric field, chain length is positively correlated with electron transfer, enhancing charge polarization. Chain length also correlates positively with dipole moment, facilitating the formation of space charge centers. While chain length minimally affects discharge active sites, the electric field can intensify their formation. Additionally, a longer chain length decreases the energy gap, increasing electron trap levels more than hole trap levels, thus capturing charges longer. Chain length is negatively correlated with ionization energy, promoting electron impact ionization, and has little effect on the excitation energy of S(0) → S(1), making excitation under high electric fields unlikely. [ABSTRACT FROM AUTHOR]

In this study, we present a detailed analysis of atomic properties for Kr XIX, specifically focusing on the lowest 128 fine-structure levels originating from the 3 s 2 3 p 6 , 3 s 2 3 p 5 3 d , 3 s 3 p 6 3 d and 3 s 2 3 p 4 3 d 2 configurations. We report energy levels, lifetimes, wavelengths, weighted oscillator strengths, and transition probabilities for multipole transition types (E1, E2, M1, and M2). To achieve this, we employed the GRASP2018 code, which implements the fully relativistic multiconfigurational Dirac–Hartree–Fock method and accounts for Breit interaction and quantum electrodynamic effects. We performed another set of calculations using the many-body perturbation theory implemented in the flexible atomic code (FAC). By comparing the results obtained from GRASP2018 and FAC, we established the accuracy and consistency of our calculations. Furthermore, using the relativistic distorted wave theory, we studied electron impact excitation of all transitions to upper levels from the ground and metastable levels and reported excitation cross sections for incident electron energies up to 5 keV. To enhance the practical utility of our findings, we also provided analytical fittings of these cross sections and excitation rate coefficients for their applications in plasma modeling. This work contributes to the atomic properties and excitation cross sections of Kr XIX, addressing a marked gap in the available atomic data. • The atomic data for Kr XIX, required for fusion plasma research, is scarce. • The study reports atomic data for 128 lowest levels of Kr XIX. • MCDHF and MBPT methods are used to calculate the atomic parameters. • The statistical approach is used to assign uncertainty in line strengths. • RDW method is applied to obtain electron impact excitation cross sections. • Excitation rates are determined assuming a Maxwellian electron energy distribution. [ABSTRACT FROM AUTHOR]

The Chemical Weapons Convention (CWC) is a science-based international treaty for the disarmament and non-proliferation of chemical weapons. However, reference Orgaization for prohibition of chemical weapons (OPCW) central analytical database (OCAD) of structures with mass spectra (MS) and retention indices (RI) includes only minor part of all possible chemical species defined in the Schedules of CWC. In this work we employed OCAD in silico augmentation based on chemoinformatics approach for chemical structures enumeration, MS data generation based on message passing neural network and based on P-alkyl molecular pairs RI prediction to support the verification activities as provided for in the CWC. Enumerated 879 noncyclic and 5270 monocyclic alcohols became the basis for generating hundreds of thousands molecules of Schedule 1 toxic chemicals like Sarin, Tabun, VX and Novichok. Trained on ordinary and neutral loss electron ionization mass spectrometry (EI-MS) a message-passing neural network (MPNN) outperformed other quantum chemistry and machine learning methods. Generated by this MPNN in silico EI-MS are very similar to the library's spectra and allowed to reach desired match factor above 800 within a scale of 0–1000. Statistical data for molecular pairs based on P-alkyl fragments was collected and used to predict RIs within desired 20 RI window for some toxic chemicals of Schedule 1.A.01, for which in the current OCAD version RIs are absent. [Display omitted] • Over 400 000 chemical structures covered by Chemical Weapon Convention (CWC) were enumerated. • Retention index for CWC compounds were calculated with molecular pairs. • Electron ionization mass spectra for CWC compounds can be predicted with artificial intelligence. • Proposed prediction method outperforms other approaches with mean match factor over 800. [ABSTRACT FROM AUTHOR]

An extensive spectroscopic investigation of Kr+ plasma has been carried out through a comprehensive collisional-radiative plasma model along with the calculations of electron impact excitation cross-sections. The fully relativistic distorted wave method has been employed to calculate the detailed electron impact cross-sections for the transitions from the ground state, four metastable states of 4 p 4 4 d and a quasi-metastable state of 4 p 4 5 s to the fine structure levels of 4 p 4 n 1 s 7 ≤ n 1 ≤ 9 , 4 p 4 n 1 p , 4 p 4 n 2 d 6 ≤ n 2 ≤ 9 and 4 p 4 n 3 f 4 ≤ n 3 ≤ 9 excited states. For this purpose, the relativistic multi-configuration Dirac-Fock method is applied to compute the Kr+ ionic structure, Kr+ ion bound-state wave functions, excitation energies, oscillator strengths and transition probabilities. These results are compared with the previously reported values. Further, the complete set of electron impact excitation cross-sections has been incorporated in the collisional-radiative model along with the other relevant kinetic processes, viz. electron impact ionization, de-excitation, three-body recombination, and radiative decay. To validate the reliability of the electron collision data and the present collision radiative model, the measurements of Mar et al [J. Phys. B: At. Mol. Opt. Phys. 39 3,709 (2006)] at 40 μs and 90 μ s instants of plasma lifetime have been utilized for the diagnosis of experimentally measured pulsed discharge Kr+ plasma at 3.3 × 10 3 Pa. The measured line emissions from Kr+ in the wavelength range of 457–485 nm are compared with the intensities obtained from the present theoretical collision radiative model to obtain the plasma parameters such as electron temperature (T e) and electron density (n e). The electron temperature results at 40 μs and 90 μ s reported by Mar et al obtained through the Boltzmann plots, have been compared with the values obtained from the present collision radiative model. [Display omitted] • Developed a collisional radiative (CR) model for the diagnostics of Kr+ Plasma. • Electron excitation cross-section of Kr+ has been calculated for several states. • Relativistic bound state wave functions of Kr+ have been obtained using MCDF approach. • The excitation energies and transition parameters are reported. • The plasma parameters are reported at different instants of plasma lifetime. [ABSTRACT FROM AUTHOR]

The cross-sections and Maxwellian rate coefficients of electron impact single ionization is theoretically investigated for tungsten ions (W64+ to W71+) for fine structure levels of configurations containing n = 2 orbitals. To check the accuracy of calculated cross-sections and rate-coefficients, detailed comparison between result from different approximations, binary encounter dipole (BED), distorted wave (DW) and coulomb born exchange (CBE) is presented. The calculations for electron impact ionization cross-sections of ground state are carried out for energy range 20 keV–1000 keV of final electron and Maxwellian rate coefficients for ground state are evaluated at the temperature range 20 keV–300 keV. We have also provided cross-sections at five different energies and rate-coefficients at five different temperatures. The present study of tungsten ions may be useful in fusion plasma modelling and in future comparison. • Electron impact ionization cross-section of tungsten ions are presented. • Maxwellian rate coefficients of tungsten ions are provided. • Electron impact ionization cross-sections are studied using BED, DW and CBE methods. • Maxwellian rate coefficients are studied using BED, DW and CBE methods. [ABSTRACT FROM AUTHOR]

Liquid crystal monomers (LCMs) are of emerging concern due to their ubiquitous presence in indoor and outdoor environments and their potential negative impacts on human health and ecosystems. Suspect screening approaches have been developed to monitor thousands of LCMs that could enter the environment, but an updated suspect list of LCMs is difficult to maintain given the rapid development of material innovations. To facilitate suspect screening for LCMs, in-silico mass fragmentation model and quantitative structure-activity relationship (QSPR) models were applied to predict electron ionization (EI) mass spectra of LCMs. The in-silico model showed limited predictive power for EI mass spectra, while the QSPR models trained with 437 published mass spectra of LCMs achieved an acceptable absolute error of 12 percentage points in predicting the relative intensity of the molecular ion, but failed to predict the mass-to-charge ratio of the base peak. A total of 41 characteristic structures were identified from an updated suspect list of 1606 LCMs. Multi-phenyl groups form the rigid cores of 85% of LCMs and produce 154 characteristic peaks in EI mass spectra. Monitoring the characteristic structures and fragments of LCMs may help identify new LCMs with the same rigid cores as those in the suspect list. [Display omitted] • A suspect list of 1606 LCMs is updated. • Multi-phenyl groups form the rigid cores of 85% of LCMs. • 41 characteristic structures representing rigid cores of LCMs were identified. • 154 characteristic ion peaks were identified in EI mass spectra of LCMs. [ABSTRACT FROM AUTHOR]

• Description of a new representation of non-targeted LC-MS data: Molecular Barcode™. • Similarity analysis of soy-, dairy- and animal tissue-based food products. • Rationale of a semi-targeted method to detect animal tissue. • Detection of animal tissue in food products, using p G+ and related fragments. • Discussion about possible applications of the presented convergent approach. There are various analytical techniques available to address the growing interest in the composition of food products. LC-HRMS(/MS) is the most comprehensive technique, providing detailed information at the molecular level. However, given the vast number of different molecules encountered in food products, it is important to obtain a global overview of the dataset before focusing on similarities and differences. Therefore, a convergent strategy was employed, going from non-targeted to targeted analysis, with insightful data representations, most notably Molecular Barcode. Additionally an intermediate, semi-targeted analysis was defined, aimed at the specific detection of animal tissue in food products, using p G+ and related fragments after all ion fragmentation. The use of Molecular Barcode as a starting point to obtain relevant molecular data was also demonstrated. In conclusion, the convergent approach facilitates the design of suitable targeted methods, either to discriminate between samples or to find a generic target. [ABSTRACT FROM AUTHOR]

The electronic stopping power of Zn for energetic protons is studied by using a nonequilibrium approach based on real-time time-dependent density-functional theory combined with molecular dynamics simulations. We calculated the electronic stopping power of protons traveling along two channeling trajectories depending on the impact parameter and off-channeling trajectories, and revealed the mechanism for d -electron excitation. In the low-velocity range, we reproduced not only the velocity proportionality of the stopping power of Zn for protons, but also the smooth transition between two velocity proportionality regimes, which is ascribed to the gradually increasing efficiency for d -electron excitation. The off-channeling electronic stopping power is in a good agreement with experimental data in the low and middle-velocity regimes. Our results showed that the contribution of d -electron excitation to the electronic stopping is remarkable in the high-velocity regime. [ABSTRACT FROM AUTHOR]

This work is a short review on the experimental cross sections for water ionization due to the impact of light ions (Z ≤ 6), including related processes such as electron capture and water molecule fragmentation. These cross sections are crucial in studies dealing with the biological effects produced by the impact of ions on living beings. Physical interpretations of the experimental results are also provided. • Experiments on ionization and charge transfer in water impacted by light ions are reviewed. • A brief theoretical introduction is offered for supporting the analysis. • A profound physical discussion of the results is carried out. • One- and two-center effects in secondary electron emission are discussed. • The relation of these effects and First-Born and CDW approximations are commented. [ABSTRACT FROM AUTHOR]

This study investigates the global ionospheric responses at different altitudes during the geomagnetic storm in September 2017 by using the observations from IGS GIMs and GRACE, TerraSAR-X, COSMIC, Metop LEO satellite missions. According to different satellite heights, a hierarchical subtraction method is proposed to characterize the disturbance of total electron content (TEC) at the vertical regions of below 340 km , 340 ∼ 520 km , 520 ∼ 800 km and above 800 km , respectively. The integrated TEC from IRI-Plas2017 are applied to verify the feasibility and rationality of the proposed method and the electron density (Ne) profiles from the ionosonde and radio occultation (RO) measurements are used to explore the variations of Ne in different height regions. The resulting TEC disturbances (Δ TEC) on a global scale show that: 1) There was significant increase on Ne peak in F2 region during the magnetic storm, due to the strong recombination in the lower ionosphere while more intense electron ionization in the upper ionosphere; 2) During the main phase, TEC enhancement had a tendency to drift westward, which may correlate with the twice Dst minimums. 3) The east–west and north–south hemispheric asymmetry of Δ TEC exist simultaneously in this magnetic storm. However, the former is mainly attributed to ionospheric plasma bubbles, while the latter might be the seasonal thermospheric effects or the energetic particle emissions. [ABSTRACT FROM AUTHOR]

The L-shell x-rays of Te have been measured for the impact of protons with energies from 100 to 300 keV, and He2+ ions in the energy range of 300–600 keV. The new experimental data of Te for individual L-subshell and total L x-ray production cross sections were extracted from the thick-target analysis of x-ray yields. This is significant for updating the existing database. The cross sections were also compared with theoretical calculations of BEA, PWBA, ECPSSR and ECUSAR along with various atomic parameter databases and including modification of multiple ionization. On the whole, The ECUSAR-MI predictions using Campbell's atomic parameters present a best agreement to the experimental data. [ABSTRACT FROM AUTHOR]

• Laminar, fully developed two-phase flow in an arbitrary cross-section tube. • Behavior of the velocity and shear stress investigated near the triple point. • Local treatment and solution obtained independent of the tube's cross section. • Mathematical tools used to obtain a simple analytical solution. In this study, we propose a simple approach for examining the local behavior of the velocity and shear stresses in the vicinity of a triple point (TP) in a two-phase flow. We assume a laminar steady, fully developed, stratified two-phase flow with any contact angle, α , independent of the shape of the tube's cross-section. The axial component of the fluid's velocity can be treated as a scalar function in two dimensions that obeys Poisson's equation, together with the no-slip condition on the boundary (tube walls) and appropriate conditions on the interface between the phases. In our opinion, the exact solutions described in previous studies (for the special case of a cylindrical tube) are complicated and difficult to follow. Moreover, the approximated interface presented in previous studies predicts a geometric contact angle (α g e o m e t r y) that might not coincide with the physical contact angle, α , which is located at the real interface's shape. The exact solutions numerically solve the global problem for a circular tube (i.e., they find the velocity and shear stresses) and analytically obtain results in the vicinity of the TP to solve the problem with the aid of the residue theorem. However, we begin in the vicinity of the TP and our entire analysis focuses within this domain. To simplify the calculations, three steps are suggested: 1) zooming in on the TP allows us to approximate the curved arcs of the walls and the interface as straight lines (the tangents of the arcs of the wall and the outward ray of the interface) 1 1 Intuitively, for a local observation up to first order in distance, a regular curve can be approximated as a straight line; i.e., an arc can be approximated to a cord. Up to second order, a curve can be approximated as a circle. For a formal proof that Laplace's equation for the region is bounded by the wall circle (radius R w a l l), the interface circle (radius R i), and our radius R defined in Fig 2.2, a possible option is to Möbius-transform the wall circle and the interface circle into straight lines concurrent in the angle α (so the other meeting points of these circles are mapped onto the point at infinity), and to obtain the Laplace solution, thereby proving that when R / (min (R w a l l , R i n t e r f a c e)) < < 1 , the deviation tends to zero. ; 2) attaching a polar coordinate system where the origin of this coordinate system is located at the TP; and 3) suppressing the local driving forces and expressing distant driving forces as a function on the boundary, thereby leaving the velocity as a harmonic function. The proposed method can be converted for electromagnetism near a junction of several dielectric materials. Furthermore, the electromagnetic parallel problem can be extended to three dimensions; i.e., a junction point of prisms with different dielectric constants. [ABSTRACT FROM AUTHOR]

• The bremsstrahlung DDCSs are measured at 90° with 5–25 keV electrons for C and Al. • The bremsstrahlung photons are measured down to 1–2 keV. • The measured DDCSs are compared with OB and SA theories. • It is found that the discrepancies between the measured data and the theories exist. Absolute measurements of the bremsstrahlung double differential cross sections (DDCSs) for photons radiated at 90° generated by the collisions of 5–25 keV electrons and down to 1–2 keV photon energy with two thin targets C (Z = 6) and Al (Z = 13) are presented. A parallelized version of the PENELOPE Monte Carlo program has been used to correct the effects of electron multiple scattering and the backscattering from the target substrate on the experimental results. Comparisons between the experiments and the theories reveal some discrepancies between the measured data and the theoretical bremsstrahlung predictions. [ABSTRACT FROM AUTHOR]

We present the design, synthesis, computational analysis, and biological assessment of several acrylonitrile derived imidazo[4,5- b ]pyridines, which were evaluated for their anticancer and antioxidant properties. Our aim was to explore how the number of hydroxy groups and the nature of nitrogen substituents influence their biological activity. The prepared derivatives exhibited robust and selective antiproliferative effects against several pancreatic adenocarcinoma cells, most markedly targeting Capan-1 cells (IC 50 1.2–5.3 μM), while their selectivity was probed relative to normal PBMC cells. Notably, compound 55 , featuring dihydroxy and bromo substituents, emerged as a promising lead molecule. It displayed the most prominent antiproliferative activity without any adverse impact on the viability of normal cells. Furthermore, the majority of studied derivatives also exhibited significant antioxidative activity within the FRAP assay, even surpassing the reference molecule BHT. Computational analysis rationalized the results by highlighting the dominance of the electron ionization for the antioxidant features with the trend in the computed ionization energies well matching the observed activities. Still, in trihydroxy derivatives, their ability to release hydrogen atoms and form a stable O–H⋯O•⋯H–O fragment upon the H• abstraction prevails, promoting them as excellent antioxidants in DPPH• assays as well. [Display omitted] [ABSTRACT FROM AUTHOR]

End-of-life electric and electronic devices stand as one of the fastest growing wastes in the world and, therefore, a rapidly escalating global concern. A relevant fraction of these wastes corresponds to polymeric materials containing a plethora of chemical additives. Some of those additives fall within the category of hazardous organic compounds (HOCs). Despite the significant advances in the capabilities of analytical methods, the comprehensive characterization of WEEE plastic remains as a challenge. This research strives to identify the primary additives within WEEE polymers by implementing a non-target and suspect screening approach. Gas chromatography coupled to time-of-flight mass spectrometry (GC-QTOF-MS), using electron ionization (EI), was applied for the detection and identification of more than 300 substances in this matrix. A preliminary comparison was carried out with nominal resolution EI-MS spectra contained in the NIST17 library. BPA, flame retardants, UV-filters, PAHs, and preservatives were among the compounds detected. Fifty-one out of 300 compounds were confirmed by comparison with authentic standards. The study establishes a comprehensive database containing m/z ratios and accurate mass spectra of characteristic compounds, encompassing HOCs. Semi-quantification of the predominant additives was conducted across 48 WEEE samples collected from handling and dismantling facilities in Galicia. ABS plastic demonstrated the highest median concentrations, ranging from 0.154 to 4456 μg g−1, being brominated flame retardants and UV filters, the families presenting the highest concentrations. Internet router devices revealed the highest concentrations, containing a myriad of HOCs, such as tetrabromobisphenol A (TBBPA), tribromophenol (TBrP), triphenylphosphate (TPhP), tinuvin P and bisphenol A (BPA), most of which are restricted in Europe. [Display omitted] • Non-target screening analysis for the identification of hazardous substances in WEEE. • More than 300 volatile and semi-volatile substances were identified in WEEE plastic. • Flame retardants, UV filters and PAHs exhibited the highest detection frequencies. • TBBPA and TPhP displayed the highest concentrations. [ABSTRACT FROM AUTHOR]

M-subshell X-ray production cross sections were indirectly measured for Ir and Bi targets irradiated with monoenergetic electron beams. The projectile energy range ran from 2.2 to 28 keV, impinging on Ir and Bi pure bulk targets in a scanning electron microscope. The resulting X-ray emission spectra were acquired with an energy dispersive spectrometer, and processed afterwards by means of a robust parameter optimization procedure developed previously. X-ray production cross sections were finally obtained through an approach involving an analytical prediction for the emission spectra, which relies on the ionization depth distribution function. The values obtained by this approach were compared with empirical and theoretical predictions, appealing to different relaxation data taken from the literature. • M-subshell X-ray production cross sections were indirectly measured for Ir and Bi. • The electron energy range ran from 2.2 to 28 keV. • X-ray production cross sections were assessed on the basis of the ionization depth distribution function. • The values obtained by this approach were compared with empirical and theoretical predictions. [ABSTRACT FROM AUTHOR]

The plant secondary metabolite families of coumarin and 4-hydroxy coumarin have a broad pharmacological spectrum ranging from antibacterial to anticancer properties. One prominent member of this substance class is the synthetic but naturally inspired anticoagulant drug and rodenticide warfarin (coumadin). A vast number of publications focus on the identification of warfarin and its major cytochrome P450-mediated phase I metabolites by liquid chromatography (LC) with mass spectrometry (MS) and tandem mass spectrometric (MS/MS) detection techniques. For the first time, electron ionization (EI) induced high-resolution quadrupole time-of-flight mass spectrometric (HR-qToF-MS) data of in-liner derivatized warfarin and selected hydroxylated species is provided in this study as an alternative to LC-MS/MS approaches. Furthermore, the characteristic fragments and fragmentation pathways of the analyzed methyl ethers are concluded. The obtained data of analytical standards, specific deuterated and 13C-labeled compounds prove inductive cleavage of the acyl or acetonyl side chain, methyl migration, and H -migration, along with consequential inductive cleavage as predominant fragmentation routes. Based on the HR-spectral data, commonalities and differences between the analyzed compounds and fragment groups were evaluated with future applicability in structure elucidation and spectra prediction of related compounds. [Display omitted] • Electron Impact Ionization High-Resolution Mass Spectrometry of Warfarin. • Fragmentation Pathways of Derivatized Warfarin and Hydroxylated Warfarin Species. • Inductive Cleavage of the Acyl or Acetonyl Side Chain, Methyl Migration, and H -Migration Along With Consequential Inductive Cleavage are Predominant Fragmentation Routes. [ABSTRACT FROM AUTHOR]

In this work, we propose a distorted wave method in the relativistic framework to analyze the electron collision ionization process under the influence of strongly coupled semi-classical plasmas. A pseudopotential is used to represent the screened interactions between the core and outer electron, together with solving the Dirac equation to take care of the relativistic effects. This potential characterizes the plasma in terms of the Debye screening length and the de Broglie wavelength, which takes into account both the quantum mechanical effects of diffraction (short distance) and the collective effects (long distance). With this method, the traditional central-field potential is modified, the bound- and continuum-electron wavefunctions and the collision matrix elements are estimated under a relativistic Dirac–Coulomb framework. The strongly coupled semi-classical plasma effects on the energies, transition rates, and the electron impact ionization cross sections are investigated in detail, using the hydrogen atom as an example. Our results agree well with other available theoretical data. The reported results and the computational scheme are not only of interest to the communities such as atomic and plasma physics, but also have implications for many other areas, including astrophysical objects, inertial confinement fusion plasmas, etc. • Effects of strongly coupled semi-classical plasmas on the hydrogen atom is studied. • Our method yielding plasma dependent energies and ionization cross sections. • This study has far-reaching implications for astrophysical objects, fusion plasmas, etc. [ABSTRACT FROM AUTHOR]

The consecutive transients (CT) method is a diagnostics approach combining experimental and computational techniques to probe the plasma parameters of Charge Breeder Electron Cyclotron Resonance Ion Sources (CB-ECRIS). The method is based on short pulse injection of singly charged ions into the charge breeder plasma, and the measurement of the resulting transients of the charge bred multiply charged ions. Estimates for plasma density, average electron energy and characteristic times of ion confinement, electron impact ionisation and charge exchange are then computationally derived from the experimental data. Here the CT method is applied for parametric studies of CB-ECRIS plasma. Potassium ions were charge bred with hydrogen support plasma, and the effects of varied microwave power, neutral gas pressure and magnetic field strength on the plasma parameters and charge breeding efficiency are presented. It is shown that the method is sufficiently sensitive to provide relevant information on changing plasma conditions with the control parameters. The neutral gas pressure had the strongest impact on the plasma parameters, and the results agree with trends obtained by using other diagnostic methods, e.g. the increase of plasma density with increased neutral gas pressure. Furthermore, the method can provide information inaccessible with other methods, such as the characteristic times of ion confinement, ionisation and charge exchange — and the hierarchy between them. The results show that the peak charge breeding efficiency is obtained for the highest ion charge state for which the ionisation time remains shorter than the charge exchange and the ion confinement times. [ABSTRACT FROM AUTHOR]

This work analyzes the scale-dependent dynamics and stability of spinning beams with circular and rectangular cross-sections in complex environments based on the nonlocal strain gradient theory (NSGT). To model the system, surface energy, rotary inertia effect, and scale effects along the thickness direction are considered. The surface elasticity theory and Rayleigh beam model are adopted to extract the dynamical equations. The eigenvalue problem is solved by employing the Laplace transform and the Galerkin discretization procedure, and the vibrational frequencies are detected accordingly. Also, according to the stability theory of gyroscopic systems, the system instability threshold is recognized analytically. Campbell diagrams and stability graphs are examined for comprehending the divergence and flutter behaviors. The impacts of geometry, scale factor, asymmetrical cross-sections, thermal fields, hygro-magnetic loads, follower and axial forces, and various shear and elastic foundations on the dynamical behavior of the system are interpreted. The results revealed that the system stability evolution could be substantially altered by considering the rotary inertia effect and variations of the cross-section geometry. It is demonstrated that, unlike the rotary inertia effect, the stable regions of the system are significantly expanded by considering the scale effects along the thickness direction. It is also found that the stabilizing effect of surface energy is amplified for low/high values of the diameter/length. The present research outcomes can offer valuable practical guidelines for spinning nanoengineering applications. • Magneto-hygro-thermo-mechanical vibration analysis of embedded spinning nanobeams. • Surface energy, rotary inertia effects, scale impacts along the thickness direction. • Divergence and flutter instabilities of the system with axisymmetric cross-sections. • Campbell diagram, stability maps, and frequency analysis. • Laplace transform and the Galerkin discretization approach to solve model equations. [ABSTRACT FROM AUTHOR]

Atomic structure parameters for levels corresponding to 2 s 2 2 p 6 3 s 2 3 p 4 , 2 s 2 2 p 6 3 s 3 p 5 , 2 s 2 2 p 6 3 s 2 3 p 2 3 d 2 , 2 s 2 2 p 6 3 s 3 p 4 3 d and 2 s 2 2 p 6 3 s 2 3 p 3 3 d configurations of S-like Xe 38 + are calculated using the fully relativistic multiconfiguration Dirac-Hatree-Fock (MCDHF) method followed by the subsequent relativistic configuration interaction (RCI) calculations. The parameters evaluated include energies of the lowest 75 levels and E1, M1, E2, and M2 transition parameters among these levels. The effect of the choice of virtual orbitals for generating the wavefunctions is discussed. The accuracy of our line strengths is established through the rigorous calculations of their associated uncertainties using three different methods. Another set of calculations using the many-body perturbation theory (MBPT) to validate the present MCDHF-RCI energies is carried out. Further, the electron impact excitation cross-sections using the relativistic distorted wave (RDW) theory are determined for all transitions from the ground and metastable states in the incident electron energy range from the excitation threshold to 10 keV. For plasma physics applications, the fitting parameters for these cross sections employing two distinct equations tailored for low and high-energy regimes are reported. Moreover, the rate coefficients are determined in the electron temperatures range of 15 eV to 100 eV by taking into account the Maxwellian electron energy distribution function and our computed cross-sections. In addition to addressing the atomic data gap in highly charged Xe ions, the present results are of good accuracy and can serve as benchmark tests for other theoretical evaluations. Moreover, they can also assist in line identification of the complex spectra of highly charged sulphur-like xenon ions. [Display omitted] • Relativistic calculations for energies and transition parameters using the MCDHF-RCI and MBPT methods for 75 levels of Xe38+ are performed • Uncertainties in transition parameters are estimated using three different statistical approaches • EIE cross sections from ground/ metastable states to higher levels for incident electron energies up to 10 keV are reported • Maxwellian-averaged excitation rate coefficients are also calculated for electron temperatures ranging from 15–100 eV [ABSTRACT FROM AUTHOR]

Equilibrium charge-state fractions F q and average charges 〈 q 〉 are calculated for low-charged Hf q + , W q + and Os q + ions with the charges q = 0–3 colliding with He atoms at energies E = 0.5–25 keV/u. F q and 〈 q 〉 values are obtained on the basis of electron-capture and electron-loss cross sections calculated by ARSENY and DEPOSIT codes briefly described in the paper. Calculated cross sections, F q and 〈 q 〉 values, calculated also for other low-energy ion–atom collisions, are compared with available experimental data. The present results may be of interest for specialists studying low-energy beams of rare isotopes of Hf, W and Os ions. [ABSTRACT FROM AUTHOR]