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Hybrid spin-exchange optical pumping is widely used in precision measurements and tests of fundamental physics. In these researches and applications, accurate measurement of the spin polarizations of hybrid alkali atoms and noble gas atoms has a significant role. Here we propose a novel method of measuring the spin polarizations of hybrid K-Rb and $^{21}Ne$ atoms simultaneously. We study the mixture of the slowing-down factors of hybrid alkali atoms due to spin-exchange interactions between hybrid alkali atoms, and the resonance-frequency shift of alkali atoms due to spin-exchange interactions with noble-gas atoms. We investigate the relationship between the hybrid resonance frequency and the polarizations. The spin polarizations of alkali atoms and noble-gas atoms have been measured based on this method, which is from 0.082 to 0.756 and from 0.018 to 0.124 with uncertainties smaller than 10.4 % and 12.7 % respectively. This method is promising for the applications requiring simultaneous and real-time measurement of the polarizations of alkali and noble-gas atoms, such as inertial sensors and tests of fundamental physics.

Alkali metal-noble gas comagnetometers operated in the regime of spin-exchange relaxation-free (SERF) have been widely used in fundamental physics tests and rotation sensing as gyroscope. Spin-exchange relaxation is an important systematic bias of the comagnetometer, which could limit sensitivity significantly. However, the suppression effect of the spin-exchange relaxation has not been examined quantitatively so far. Herein, we systematically investigate the relaxation of the alkali metal atoms and find that the spin-exchange relaxation is not completely eliminated under the normal operating condition of the K-Rb-21Ne comagnetometer. In addition to the optical pumping rate, the spin-exchange relaxation still plays a dominant role in the broadening of electron Zeeman resonances due to the large electron magnetic field. This is the first demonstration that the alkali metal atoms are operated in the near-SERF regime in the alkali metal-noble gas comagnetometer with a large election magnetic field, which will shed light on the way to reduce the relaxation of the alkali metal atoms and enhance the sensitivity of the comagnetometer.

As the measurement of multiple parameters in a spin-exchange relaxation-free (SERF) comagnetometer requires a long time and complex experimentation, we present a novel dynamic frequency response-based method for the accurate and rapid measurement of key parameters in a SERF comagnetometer. By testing the dynamic frequency response to a transverse oscillating magnetic field, we can obtain multiple parameters simultaneously and quickly without interrupting the operation of the comagnetometer. This method simultaneously measures the nuclear longitudinal relaxation rate and alkali metal number density within minutes, with uncertainties of less than 20.8% and 14.0%, respectively. The main error sources in the nuclear longitudinal relaxation rate and alkali metal number density are the spin-exchange rate constant and spin-exchange enhancement factor, respectively. In addition, the polarization of alkali metal and noble gas atoms can be obtained during the experimental process, and the fast measurement of these parameters is beneficial for applications requiring simultaneous and in situ measurement of spin ensemble performance.

In this Letter, we investigate the non-dipole effects in time delay of photoelectrons emitted by multi-electron atoms, negative ions, and respective endohedrals. We present the necessary general formulas in the frame of the random phase approximation with exchange (RPAE) applied to atoms, negative ions, and properly adjusted to endohedrals. We concentrate on low photon energy region, where non-dipole effects are very small in the cross-sections but become observable in angular distributions. We not only derive the formulas for non-dipole effects in time delay, but perform corresponding numeric calculations. We demonstrate how the non-dipole corrections can be isolated in experiment. Concrete calculations are performed for noble gas atoms Ar and Xe, isoelectronic to them negative ions Cl- and I- and endohedrals Ar(Cl-)C60 and Xe(I-)@C60. We found that the forward-backward photoelectron time delay differences give direct information on non-dipole effects. They proved to be quite measurable and prominently affected by the presence of the fullerenes shell., Comment: 14 pages, 4 figures

Two-phase noble liquid detectors are widely used in experiments for dark matter search. Ionization signals caused by particle scattering in a noble-gas liquid are commonly recorded using the effect of proportional electroluminescence in the gas phase. In addition to the standard electroluminescence mechanism based on vacuum ultraviolet emission of noble gas excimers, the mechanism of electron bremsstrahlung on neutral atoms with a continuous spectrum from ultraviolet to near infrared range was recently revealed. In this paper, we demonstrate the effect of bremsstrahlung on characteristics of a DarkSide-50 two-phase argon detector. In particular, the sag of the electroluminescent gap grid and the contribution of the fast component to the proportional electroluminescence signal will be estimated.

Liquid noble gases are widely used as targets in low background search experiments, particularly in direct dark matter search experiments. 83mKr is an excellent low-energy internal calibration source for future larger liquid noble gas detectors. To calibrate liquid argon detector with 83mKr in different drift fields and to study the correlation between light yield and drift fields. A dual-phase LAr prototype detector was designed to study the 83mKr responses in liquid argon. 83mKr atoms are produced through the decay of 83Rb and introduced into the LAr detector through the circulating purification system. We report that the light yield reaches 7.26 ± 0.02 pe/keV for 41.5 keV from 83mKr and 7.66 ± 0.01 pe/keV for 511 keV from 22Na, as a comparison. After stopping the fill, the rate decays of 83mKr are with a fitted half-life of 1.83 ± 0.11 h, which is consistent with the reported value of 1.83 ± 0.02 h. The light yield that varies with the drift electric field from 0 to 200 V/cm has also been reported.

We have studied the compression behaviors of Ne, Ar, and Kr in comparison with the isoelectronic counterparts of NaF, KCl, and RbBr to 120 GPa, using in situ angle-resolved x-ray diffraction. Interestingly, the pressure-volume compression data indicate the emergence between the isoelectronic pairs of NaF/Ne $g60\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$, KCl/Ar $g30\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$, and RbBr/Kr $g25\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$---analogous to that previously observed in CsI/Xe $g80\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$. The interatomic distances of the isoelectronic pairs also become similar as pressure increases, within the difference of $\ensuremath{\sim}3%$, underscoring the pressure-induced electron polarization in novel gas solids, stronger in Xe and getting weaker in Kr, Ar, and Ne. In contrast, the compression curves and interatomic distances of He and LiF remain distinctive to 200 GPa.

We present a broad study of linear, clustered, noble gas puffs irradiated with the frequency doubled (527 nm) Titan laser at Lawrence Livermore National Laboratory. Pure Ar, Kr, and Xe clustered gas puffs, as well as two mixed-gas puffs consisting of KrAr and XeKrAr gases, make up the targets. Characterization experiments to determine gas-puff density show that varying the experimental parameter gas-delay timing (the delay between gas puff initialization and laser-gas-puff interaction) provides a simple control over the gas-puff density. X-ray emission (>1.4 keV) is studied as a function of gas composition, density, and delay timing. Xe gas puffs produce the strongest peak radiation in the several keV spectral region. The emitted radiation was found to be anisotropic, with smaller X-ray flux observed in the direction perpendicular to both laser beam propagation and polarization directions. The degree of anisotropy is independent of gas target type but increases with photon energy. X-ray spectroscopic measurements estimate plasma parameters and highlight their difference with previous studies. Electron beams with energy in excess of 72 keV are present in the noble gas-puff plasmas and results indicate that Ar plays a key role in their production. A drastic increase in harder X-ray emissions (X-ray flash effect) and multi-MeV electron-beam generation from Xe gas-puff plasma occurred when the laser beam was focused on the front edge of the linear gas puff.

The densities of NeI atoms and XeII ions in the PS-1 mirror system were measured by the method of laser-induced fluorescence (LIF). Schemes of levels for LIF measurements of the density are proposed. Models for numerical processing of the obtained LIF signals are developed. The electron temperature and plasma density were also measured using Langmuir probes.

Two dielectric barrier discharge (DBD) reactors, one small, the other about 40 times larger, associated equipment, and a dedicated MATLAB code have been used to carry out precise determinations of electrical energy, $E_{g}$ , dissipated per discharge cycle of the applied a.c. voltage, $V_{a}$ . In the smaller reactor, this was done over the frequency range $5 \le f\le 50$ kHz and using twin pairs of several different insulating materials (2.54-cm-diameter disks) with relative permittivities between $2.1 \le \kappa _{\text {die}}^{\prime }\le 9.5$ as dielectric barriers in DBDs for four different gases: He, Ne, Ar, and N2. In the large reactor, $f$ was restricted to 20 kHz in Ar and He; this latter system primarily serves for plasma polymerization experiments in which organic “monomers” are admixed with the flow of Ar as carrier gas. We report the method for exactly evaluating $E_{g}$ , and then present and compare values measured under different conditions. To the extent possible, these are compared between the small and large reactors, and with results published in the literature. The reliability of the method is confirmed, for example, by reproducing published breakdown fields of the gases examined, and by several other original results.

The geometries, electronic structures and bonding of early actinide-noble gas complexes are studied computationally by density functional and wavefunction theory methods, and by ab initio molecular dynamics. AcHe183+ is confirmed as being an 18-coordinate system, with all of the He atoms accommodated in the primary coordination shell, and this record coordination number is reported for the first time for Th4+ and Th3+. For Pa and U in their group valences of 5 and 6 respectively, the largest number of coordinated He atoms is 17. For AnHe17q+ (An = Ac, q = 3; An = Th, q = 4; An = Pa, q = 5; An = U, q = 6), the average An-He binding energy increases significantly across the series, and correlates linearly with the extent of He  Anq+ charge transfer. The interatomic exchange correlation term Vxc obtained from the Interacting Quantum Atoms approach correlates linearly with the An-He Quantum Theory of Atoms-in-Molecules delocalization index, both indicating that covalency increases from AcHe173+ to UHe176+. The correlation energy in AnHe163+ obtained from MP2 calculations decreases in the order Pa > Th > U > Ac, the same trend found in Vxc. The most stable complexes of Ac3+ with the heavier noble gases Ar–Xe are 12 coordinate, best described as Ng12 cages encapsulating an Ac3+ ion. There is enhanced Ng  Ac3+ charge transfer as the Ng gets heavier, and Ac-Ng covalency increases.

We conduct a systematic theoretical study of strong field tunneling ionization of noble-gas atoms, from He to Kr, by elliptically polarized laser pulses in the so-called attoclock setup. Our theoretical model is based on a numerical solution of the time-dependent Schr\"odinger equation in the single active electron approximation. We simulate laboratory measurements utilizing few optical cycle pulses to benchmark our calculations against experiment. We further conduct ``numerical attoclock'' simulations with short, nearly single-cycle pulses to test various tunneling ionization models. We examine the attoclock offset angles as affected by the target orbital structure and the laser pulse intensity. Finally, we exclude a finite tunneling time scenario and attribute the attoclock offset angle entirely to the Coulomb field of the ion remainder as was recently demonstrated for the hydrogen atom [U. S. Sainadh et al., Nature (London) 568, 75 (2019)].

Through solution of the multielectron, semi-relativistic, time-dependent Schr\"{o}dinger equation, we show that angular streaking produces strongly spin-polarized electrons in a noble gas. The degree of spin polarization increases with the Keldysh parameter, so that angular streaking -- ordinarily applied to investigate tunneling -- may be repurposed to generate strongly spin-polarized electron bunches. Additionally, we explore modifications of the angular streaking scheme that also enhance spin polarization.

Inertial navigation systems generally consist of timing, acceleration, and orientation measurement units. Although much progress has been made towards developing primary timing sources such as atomic clocks, acceleration and orientation measurement units often require calibration. Nuclear Magnetic Resonance (NMR) gyroscopes, which rely on continuous measurement of the simultaneous Larmor precession of two co-located polarized noble gases, can be configured to have scale factors that depend to first order only on fundamental constants. The noble gases are polarized by spin-exchange collisions with co-located optically pumped alkali-metal atoms. The alkali-metal atoms are also used to detect the phase of precession of the polarized noble gas nuclei. Here we present a version of an NMR gyroscope designed to suppress systematic errors from the alkali-metal atoms. We demonstrate rotation rate angle random walk (ARW) sensitivity of 16&mu, Hz/Hz and bias instability of &sim, 800 nHz.

Results of the experimental investigation of the discharge front propagation in the beams of powerful terahertz (670 GHz) and sub-terahertz (263 GHz) radiation are presented. The front propagation velocity is measured in the wide pressure ranges of the noble gas (argon, krypton) mixtures with nitrogen (0.1–2 atm).

Co-auteur étranger; International audience; doi: 10.7185/geochemlet.2028 lower mantle upper mantle OIB MORB outer core Low 3 He/ 22 Ne High 3 He/ 4 He Co re C on tr ib ut io n This study investigates metal-silicate partitioning of neon (D Ne) under the likely conditions of early Earth's core formation: up to 16 GPa, ∼ 3000 K and an oxygen fugacity near IW-2 (2 log units below the Iron-Wüstite buffer). We find that the D Ne coefficients range between 10 −2 and 10 −1. These partition coefficients are only one of the controlling factors of noble gas distributions within the early Earth: because, even if D He and D Ne are low (∼10 −4), there may have been sufficient noble gases present in the mantle to supply a significant quantity of He and Ne to the core. Assuming gas-melt equilibrium of the molten proto-Earth with a nebular gas composition and con-comitant metal-silicate differentiation, the core would have inherited and maintained throughout Earth's history high 3 He/ 4 He ratios and low 3 He/ 22 Ne ratios (

International audience; Recently considerable attention focused on the development of excimers and exciplexe lamp. These lamps are sources of spontaneous radiation based on the transitions of excited molecules called excimers when pure noble gas or a mixture of several noble gases is added. The excited molecules are considered to be exciplex when the gas mixture contains one or more halogens in addition to noble gases or mercury. The de-excitation of these molecules to their dissociative fundamental states induces a loss of energy in the form of UV, visible and IR radiation. The work is based on an experimental study of a pure krypton lamp and theoretical study of the Kr/Cl2 plasma chemistry in terms of the homogenous model. The lamp is excited by a dielectric barrier discharge, the gas breakdown is obtained between two flat and identical electrodes of 5 cm × 5 cm surface area, these electrodes are insulated and separated by two dielectric plates of permittivity 4 and thickness 2 mm. The space between the two dielectrics is 2 mm and is filled with gas at pressure of 129 to 460 mbar. In order to carry out a parametric study, the influence of several parameters such as applied voltage, frequency and gas pressure was studied. A spectroscopic and kinetic analysis of a pure krypton and Kr/Cl2 mixture excilamp excited by DBD is reported here. The interpretation of the experimental and theoretical results allowed to explain chemical processes responsible of the production of excimers inducing UV emission and to link these processes to the IR emissions that control the population of the excited metastable states of krypton. These states are indirectly responsible for UV emission.

The wide range of applications using metastable noble gas atoms has led to a number of different approaches for producing large metastable state densities. Here we investigate a recently proposed hybrid approach that combines RF discharge techniques with optical pumping from an auxiliary state in xenon. We study the effect of xenon pressure on establishing initial population in both the auxiliary state and metastable state via the RF discharge, and the role of the optical pumping beam power in transferring population between the states. We find experimental conditions that maximize the effects, and provide a robust platform for producing relatively large long-term metastable state densities.

Systematic measurements on single and triple Auger decay in CO and CO2 after the creation of a C 1s or a O 1s core vacancy show that the percentage of triple Auger decay is on the order of 10−2 of the single Auger decay in these molecules. The fractions of triple Auger decay are compared with triple Auger fractions for carbon atoms and some noble gas atoms, and are found to follow a linear trend correlated to the number of valence electrons on the atom with the initial core vacancy and on its closest neighbours. This linear trend for the percentage of triple Auger decay is represented by a predictive equation TA = 0.13·Nve − 0.5.

Rescattering by electrons on classical trajectories is central to understand photoelectron and high-harmonic emission from isolated atoms or molecules in intense laser pulses. By controlling the cluster size and the quiver amplitude of electrons, we demonstrate how rescattering influences the energy distribution of photoelectrons emitted from noble gas nanoclusters. Our experiments reveal a universal dependence of photoelectron energy distributions on the cluster size when scaled by the field driven electron excursion, establishing a unified rescattering picture for extended systems with the known atomic dynamics as the limit of zero extension. The result is supported by molecular dynamics calculations and rationalized with a one-dimensional classical model.

The scaling relations for the dispersion coefficients of long-range interactions between the Mu(1s)-Mu(1s, 2s, or 2p) systems and the H(1s)-H(1s, 2s, or 2p) systems are obtained using analytical properties of hydrogenic wavefunctions, which allows us to obtain the dispersion coefficients for Mu(1s)-Mu(1s, 2s, or 2p) systems from the corresponding H(1s)-H(1s, 2s, or 2p) systems. Additionally, the dispersion coefficients of long-range interactions of Mu(1s) with the ground-state H, noble gas atoms He, Ne, Ar, Kr, and Xe, alkali-metal atoms Li, Na, K, and Rb, alkaline-earth atoms Be, Mg, Ca, and Sr, and Cu, Ag, F, and Cl atoms are calculated.

The relativistic effects on energetic quantities of the HNgF → HF + Ng (Ng = Ar, Kr, Xe, and Rn) reactions were evaluated by means of advanced four-component calculations with high-level electron correlation treatment and adequate relativistic basis sets. The results indicate that the scalar relativistic corrections can provide classical barrier height increments of as much as 4.8% (1.9 kcal mol−1) for the reaction with the heaviest noble gas, radon, while the spin-orbit coupling is almost as important in this case, lowering the value by 3.8% (−1.5 kcal mol−1). Therefore, these two relevant relativistic corrections cancel almost completely. A similar picture is seen for the energy variation from the reactant (HRnF) to the products (HF + Rn), but the contribution signs are reversed now (−4.0 and 3.4 kcal mol−1). A partial cancelling is also noticed for the HXeF → HF + Xe reaction. Such pattern is surprising since scalar relativistic effects usually predominate by magnitude orders over the spin-orbit coupling. These conclusions are reflected in the changes observed in rate constant values. Finally, an alternative decomposition route catalyzed by HF is suggested for these HNgF compounds, which can shed some light on the controversies regarding their thermal stability.

The work deals with a theoretical investigation of elastic scattering of ultrashort electromagnetic pulses (USP) on the noble gas atoms in the far ultra-violet and soft X-ray regions. The investigation is performed within the framework of a dipole approximation and the first-order quantum-mechanics perturbation theory. Major attention is given to the study of the dependence of the total probability of scattering within the pulse time on the USP duration at different carrying frequency values. It is shown that at certain values of the problem parameters this dependence is nonlinear. The calculations are performed for the corrected Gaussian pulses and wavelet pulses without the carrying frequency.

Luminescence spectra in the range 200–970 nm were studied for He, Ne, Ar, Kr, and Xe and Ar–Kr, Ar–Xe, and Kr–Xe mixtures under 5-ns electron-beam excitation. Emission intensity distributions over noble-gas 2p-levels were obtained. It was concluded that the main process for populating atomic levels was not dissociative recombination of molecular noble-gas ions with electrons. The emission intensity of heteronuclear ionic noble-gas molecules was noticeably less (relative to the intensities of the atomic lines) than for ion-beam excitation.

In this study, the infrared absorption spectra of 2-methyl-1,3-butadiene (isoprene) in noble gas matrices (Ar, Kr, and Xe) have been reported. The vibrational structure observed at cryogenic temperature, in combination with anharmonic vibrational calculations using density functional theory, helped in unambiguously assigning the fundamental modes of isoprene unresolved in the previous gas phase measurements, which would be of basic importance in the remote sensing of this molecule. A careful comparison with the most recent gas phase study [Brauer et al., Atmos. Meas. Tech. 7 (2014) 3839–3847.] led us to alternative assignments of the weak bands.

We investigated the effects of pump wavelength on terahertz wave generation via two-color laser-induced plasma in various gas targets including nitrogen and noble gases. The terahertz energy was measured as functions of pump wavelength, input pulse energy, gas species, and pressure. The results suggest that the plasmas in the heavier gases induced by relatively longer wavelength lasers are more likely to generate higher energy terahertz waves. However, the existence of phase slippage in the neutral gases causes distinct fluctuations in the terahertz energy as the gas pressure increases. Meanwhile, the terahertz waves produced in the heavier gas are more likely to saturate at relatively higher pressures or incident optical powers. We propose an ionization rate formula associated with the gas species and pump wavelength to theoretically explain the validity of the experimental results. As a result, the terahertz pulse energy approaches a maximum value of 0.099 μJ per pulse in xenon with a 1500-nm excitation laser, and the terahertz wave to optical pulse energy conversion efficiency reaches 5.6 × 10–3, which is an order of magnitude higher than that of a conventional 800-nm pump laser.

Anharmonic vibrational state calculations were performed for PtCO and Ar-PtCO via the direct vibrational configuration interaction (VCI) method based on CCSD(T) energies and CCSD dipole moments at tens of thousands of grids, to get insights into the anomalous effect of a solid argon matrix on the vibrational spectra of PtCO. It was shown that, through the binding of Ar to PtCO via a strong van der Waals interaction, the Pt-C-O bending fundamental level drastically loses the infrared intensity although the corresponding overtone band shows a relatively large intensity. The origin of this phenomenon was analyzed based on the dipole moment surfaces and electron densities around the equilibrium structure. The present computations have solved the inconsistency between the gas-phase and the matrix-isolation experiments for PtCO.

The letter reports a comparative assessment of the usefulness of the two different Grimme’s corrections for evaluating dispersion interaction (DFT-D3 and DFT-D3BJ) for the representative molecules of the family of noble-gas hydrides HXeY and their complexes with the HZ molecules, where Y and Z are F/Cl/OH/SH. with special regard to the dispersion term calculated by means of the symmetry-adapted perturbation theory (at the SAPT0 level). The results indicate that despite differences in the total interactions energy (DFT + corrections) versus SAPT0 results, the sequence of contributions of the individual dispersion terms is still maintained. Both dispersion corrections perform similarly and they improve the results suggesting that it is worthwhile to include them in calculations.

Low energy ion scattering is a technique to detect the energy of ions which are scattered from a surface. For noble gas ions, it is predominantly sensitive to the topmost surface layer due to strong neutralisation processes. Depending on the combination of projectile ion and target material, the scattering spectra can exhibit contributions resulting from multiple scattering processes in deeper layers when probing ions are re-ionised on the exiting trajectory. These events cause a pronounced continuum located toward lower scattering energies with respect to the direct scattering peak. In a previous work a semi-empirical formula has been given which allows fitting and derivation of quantitative information from the measured spectra [Nelson 1986 J. Vac. Sci. Technol. A 4 1567-1569]. Based on the former work an improved formula is derived which has less numerical artefacts and is numerically more stable., 18 pages, 8 figures, 1 table

Xenon (Xe) is a valuable and scarce noble gas used in various applications, including lighting, electronics, and anesthetics, among many others. It is also a volatile byproduct of the nuclear fission of uranium. A novel material architecture consisting of silicate nanocages in contact with a metal surface and an approach for trapping single Xe atoms in these cages is presented. The trapping is done at low Xe pressures and temperatures between 400 and 600 K, and the process is monitored in situ using synchrotron-based ambient pressure X-ray photoelectron spectroscopy. Release of the Xe from the cages occurs only when heating to temperatures above 750 K. A model that explains the experimental trapping kinetics is proposed and tested using Monte Carlo methods. Density functional theory calculations show activation energies for Xe exiting the cages consistent with experiments. This work can have significant implications in various fields, including Xe production, nuclear power, nuclear waste remediation, and nonproliferation of nuclear weapons. The results are also expected to apply to argon, krypton, and radon, opening an even more comprehensive range of applications.

Helium and neon, the two lightest noble gases, have been traditionally positioned by IUPAC in the Group 18 of the Periodic Table of Elements, together with argon, and other unreactive or moderately reactive gaseous elements (krypton, xenon, radon), and oganesson. In this account we revive the old discussion on the possible placement of helium in the Group 2, while preserving the position of neon in Group 18. We provide quantum-chemical arguments for such scenario—as well as other qualitative and quantitative arguments—and we describe previous suggestions in the literature which support it or put it into question. To this author’s own taste, He should be placed in Group 2.

When tuned for maximum sensitivity, the electron bombardment ion source on the ANU (the Australian National University) Helix MC Plus noble gas mass spectrometer produces an Ar ion beam that is mass discriminated as a function of Ar partial pressure. This effect can be reduced substantially or eliminated by adjusting the repeller and trap voltages, although with a sensitivity loss of up to 50%. A recommended procedure for tuning an ion source to reduce pressure dependent mass discrimination is described. Similar procedures can be applied to other noble gases and other ion sources to ensure that pressure dependent mass discrimination is avoided.

Molecular dynamics (MD) simulations have been used to calculate interaction-induced absorption spectra of neon-krypton mixture confined between graphite plates. The continuous phenomenological model with parameters fitted to couple clusters (CC) quantum mechanical method has been applied to calculate collision-induced dipole moments. The collision-induced dipole moment correlation functions and its 2, 3, 4-body contributions of Ne-Kr binary mixture at three temperatures have been calculated and analyzed. The dynamics of neon and krypton atoms between graphite slabs have been investigated by the mean square displacement functions and z-profile functions. The phase separation between neon and krypton has been observed at T = 100 K in the direction perpendicular to the graphite surface. We have found that collision-induced absorption spectra reflect the mobility of noble gas atoms in binary mixture between graphite slabs.

This paper discusses the validity of applied theoretical methods by which ionization coefficients were derived, assuming the Maxwellian shape of the free-electron gas spectrum in the electronegative SF6 and noble gas mixtures. It has been shown that dc breakdown voltage values calculated in such way are in a good agreement with correspondingly obtained experimental results. The predicted model has been explained by the fact that electronegative gas affects more the low-energy part of free-electron gas spectrum than the high-energy part. Since high-energy electrons have higher probability to initiate the breakdown the Paschen curve obtained under assumption of Maxwellian shape of free-electron gas spectrum does not change significantly. In addition to these observed microscopic characteristics, the influence of the gas insulation recovery time on the macroscopic characteristics was determined by adding the SF6 gas to noble gases.

An alternating current atmospheric pressure plasma jet is generated with noble gas or noble gas/oxygen admixture as working gas. A “core plasma filament” is observed at the center of the dielectric tube and extends to the plasma jet at higher peak-to-peak voltages. This type of plasma jet is believed to be of the same nature with the reported plasma bullet driven by pulsed DC power sources. Double current probes are used to assess the speed of the plasma bullet and show that the speed is around 104–105 m/s. The time dependence of the downstream bullet speed is attributed to the gas heating and in turn the increase of the reduced electric field E/N. Optical emission spectra show the dependence of helium and oxygen emission intensities on the concentration of oxygen additive in the carrier gas, with peak values found at 0.5% O2. Multiple radial jets are realized on dielectric tubes of different sizes. As a case study, one of these multi-jet devices is used to treat B. aureus on the inner surface of a plastic beaker and is shown to be more effective than a single jet.

The stability of noble gases (He, Ne, Ar, Kr and Xe) in thorium dioxide is studied by means of density functional theory. The computations are performed considering insertion sites of ThO2, including the interstitial sites, the thorium vacancies, the oxygen-thorium di-vacancy and three types of Schottky defects. Our results show that there is an approximately linear relation between the energies and the atomic radii. As the size of the noble gas atom increases, the noble gas atoms energetically prefer to incorporate into large vacancy defects rather than into interstitial positions. Moreover, the binding energy of Kr or Xe interstitial in a Schottky defect is larger than the formation energy of a Schottky defect, suggesting the Schottky defects are thermodynamically favorable in the presence of these noble gas atoms. The charged defects are also considered for noble gas atoms trapped in Th and O vacancies.

We analyzed all the noble gases in HF-soluble phases in the CI chondrite Ivuna by in-vacuum gas release using the “Closed System Step Etching” (CSSE) technique, which allows for direct noble gas measurements of acid-soluble phases. The main motivation was to investigate if there are primordial noble gases in HF-soluble phases in Ivuna, something that has not been done before in CI chondrites, as most primordial noble gases are known to reside in HF-resistant phases. The first steps under mild etching released He, Ne, and Ar with solar-like elemental and isotopic compositions, confirming that Ivuna contains implanted solar wind (SW) noble gases acquired in the parent body regolith. The SW component released in some etch steps was elementally unfractionated. This is unusual as trapped SW noble gases are elementally fractionated in most meteoritic material. In the intermediate etch steps under slightly harsher etching, cosmogenic noble gases were more prominent than SW noble gases. The HF-soluble portion of Ivuna contained primordial Ne and Xe, that was most visible in the last etch steps after all cosmogenic and most SW gases had been released. The primordial Ne and Xe in the HF-solubles have isotopic and elemental ratios readily explained as a mixture of the two most abundant primordial noble gas components in Ivuna bulk samples: HL and Q. Only small fractions of the total HL and Q in Ivuna were released during CSSE analysis; ∼3% of 20NeHL and ∼4% of 132XeQ. HL is known to reside in nanodiamond-rich separates and Q-gases are most likely carried by a carbonaceous phase known as phase Q. Q-gases were likely released from an HF-soluble portion of phase Q. However, nanodiamonds might not be the source of the HL-gases released upon etching, since nanodiamond-rich separates are very HF-resistant and the less tightly bound nanodiamond component P3 was not detected.

The sheer interstellar abundance of helium makes any bound molecules or complexes containing it of potential interest for astrophysical observation. This work utilizes high-level and trusted quantum chemical techniques to predict the rotational, vibrational, and rovibrational traits of HeHHe+, HeHNe+, and HeHAr+. The first two are shown to be strongly bound, while HeHAr+ is shown to be more of a van der Waals complex of argonium with a helium atom. In any case, the formation of HeHHe+ through reactions of HeH+ with HeH3+ is exothermic. HeHHe+ exhibits the quintessentially bright proton-shuttle motion present in all proton-bound complexes in the 7.4 micron range making it a possible target for telescopic observation at the mid-IR/far-IR crossover point and a possible tracer for the as-of-yet unobserved helium hydride cation. Furthermore, a similar mode in HeHNe+ can be observed to the blue of this close to 6.9 microns. The brightest mode of HeHAr+ is dimmed due the reduced interaction of the helium atom with the central proton, but this fundamental frequency can be found slightly to the red of the Ar-H stretch in the astrophysically detected argonium cation., 9 pages, 8 tables

The detection of the noble gas molecule ArH+ initially in the Crab nebula and elsewhere since has reinvigorated the search for naturally occurring, noble gas compounds. Additionally, proton-bound complexes are known to possess exceptionally bright vibrational modes corresponding to the shifting of the proton between the two, more massive moieties. As such, smaller column densities are required for unique detection of molecules with such intense transitions. In light of this, vibrational, rotational, and rovibrational spectroscopic data are provided here for ArHAr+, NeHNe+, and ArHNe+ to assist in laboratory characterization or even astronomical detection of these noble gas molecular cations. NeHNe+ is shown to be a surprisingly well-bound system, while the neon atom is not nearly as tightly bound to ArHNe+ in comparison. Furthermore, the reaction of the astronomically detected argonium cation with the strongly supported, potential interstellar ArH3+ cation will produce ArHAr+ with favorable energetics. Th...

The equations calculating the number of valence electrons on the boranes and heteroboranes are different from other simple condensed clusters such as the condensed organometallics and transition metal clusters. The equations calculating the number of valence electrons greatly differ between the condensed boranes and heteroboranes with the non-condensed boranes and heteroboranes too. These equations calculating the number of valence electrons on simple condensed clusters are all derived from the noble gas rule and Wade’s rule in the theory. The noble gas rule and Wade’s rule could be also applied to the high-nuclearity transition metal clusters, the equation details calculating the number of valence electrons is studied. The application ranges of the noble gas rule, Wade’s rule, and 6m+2n electron rule are extended. The calculating results are satisfying comparing with actual facts.

We present an approach for direct measurement of ultrahigh laser intensities in the range \(10^{20}\)–\(10^{24}\) W/cm\(^2\). The method is based on the use of multiple sequential tunneling ionization of heavy atoms with adequately high ionization potentials. We show that, due to the highly nonlinear dependence of tunneling ionization rates on the electromagnetic field strength, an off-set in the charge distribution of ions appears to be clearly sensitive to the peak value of intensity in the laser focus. Based on the tunnel-ionization mechanism, a simple analytic theory helps in estimating the maximal charge state produced at a given laser intensity. Our theory also allows for calculating qualitatively a distribution in charge states generated in different zones of the laser focus. These qualitative predictions are in excellent agreement with numerical simulations of the tunneling cascades, developed in the interaction of a short tightly focused laser pulse with low-density noble gas targets. The method could be particularly useful and of instrumental demand in view of the expected commissioning of several new laser facilities, capable of delivering ultra-powerful light pulses in the above mentioned domain of intensities.

The Argon gas is a chemical inert gas and utilizing to generate argon plasma. The Argon gas has a benefit easy to ionize and it's the cheapest of all noble gas. The Argon plasma has employed in many applications, especially for surface modification and activation process. The plasma diagnosis troughs experimental and modeling are needed with the purpose to understand the behavior of Argon plasma. The experimental diagnosis has done by varying the gas pressure and DC-bias voltage. The Langmuir probe has utilized to measure the electron and ion density of Argon plasma. The pressure variation shows the high electron density has produced in the high pressure. The DC-bias variation has also indicated the same trend with pressure variation. The high electron densities in the range 1.2 × 1017 to 1.4 × 1017 m3 have produced in the high DC-bias voltage. The high concentration of electron density increases the ionization process inside the chamber. The Optical Emission Spectroscopy (OES) has also employed to describe the population of species during the plasma generation. The Argon plasma species utilized to decide the function of Argon plasma in application process. Despite of that, the modeling software has also utilized to study argon plasma. The modeling software describes the behavior of argon plasma theoretically. The boundary of modeling process was simplified with DC-bias in -400V temperature in 400K, pressure in 30 to 70Pa. The modeling result has focuses in the effect of pressure variation. The modeling result indicates the electron density has increased in the high pressure. The modeling result and experimental diagnosis result indicates the same trend in the pressure variation. The modeling diagnosis as a theoretical utilizes to support experimental diagnosis result to describe the behavior of argon plasma.

In this work, we present the first demonstration of a quasi-continuous-wave diode-pumped metastable xenon laser at atmospheric pressures. Lasing in metastable noble gas species has received increased attention in the last few years as a possible high-power laser source. This demonstration shows that metastable xenon has a sufficiently broad absorption spectrum to be pumped with a broad-bandwidth diode laser. This implies that a high-power metastable xenon gas laser should be achievable using high-power pump diodes.

Oganesson (Og) is the most recent addition to Group 18. Investigations of its atomic electronic structure have unraveled a tremendous impact of relativistic effects, raising the question whether the heaviest noble gas lives up to its position in the periodic table. To address the issue, we explore the electronic structure of bulk Og by means of relativistic Kohn–Sham density functional theory and many‐body perturbation theory in the form of the GW method. Calculating the band structure of the noble‐gas solids from Ne to Og, we demonstrate excellent agreement for the band gaps of the experimentally known solids from Ne to Xe and provide values of 7.1 eV and 1.5 eV for the unknown solids of Rn and Og. While this is in line with periodic trends for Rn, the band gap of Og completely breaks with these trends. The surprisingly small band gap of Og moreover means that, in stark contrast to all other noble‐gas solids, the solid form of Og is a semiconductor., Breaking rank: The electronic structure of the noble‐gas solids of neon to oganesson was investigated by means of relativistic density functional theory and many‐body perturbation theory. This revealed band gaps of 7.1 eV and 1.5 eV for the unknown solids of Rn and Og, which means that, in stark contrast to all other noble gases, solid Og is a (short‐lived) semiconductor.

The search for possible, natural, noble gas molecules has led to quantum chemical, spectroscopic analysis of NeCCH+, ArCCH+, and ArCN+. Each of these systems has been previously shown to be a stable minimum on its respective potential energy surface. However, no spectroscopic data are available for laboratory detection or interstellar observation of these species, and the interstellar medium may be the most likely place in nature where these noble gas cations are found. The bent shape of NeCCH+ is confirmed here with a fairly large dipole moment and a bright C–H stretching frequency at 3101.9 cm−1. Even if this molecule is somewhat unstable, it is likely observable now that the spectral ranges of where to look have been established. ArCCH+ is much more stable but has dim double harmonic intensities for the vibrational fundamentals and a dipole moment below 0.5 D making its rotational transitions likely buried in the astronomical weeds. Even so, ArCCH+ cannot be excluded as a possibility in laboratory experiments of hydrocarbons in argon-rich environments. ArCN+, on the other hand, has a dipole moment of greater than 3.5 D, an observable C–N stretching fundamental at 2189.6 cm−1 (4.567 microns), and a viable formation pathway through HCN, a highly-abundant interstellar molecule. Consequently, these molecules containing noble gas atoms are spectroscopically classified at high-level for the first time and may be present in observable regions of outer space.

We report both kinetic energy and angular distributions for He and Ar atoms evaporating from C12H26. All results were obtained by performing molecular dynamics simulations of liquid C12H26 with around 10-20 noble gas atoms dissolved in the liquid and by subsequently following the trajectories of the noble gas atoms after evaporation from the liquid. Whereas He evaporates with a kinetic energy distribution of (1.05 ± 0.03) × 2RT (corrected for the geometry used in experiments: (1.08 ± 0.03) × 2RT, experimentally obtained value: (1.14 ± 0.01) × 2RT), Ar displays a kinetic energy distribution that better matches a Maxwell-Boltzmann distribution at the temperature of the liquid ((0.99 ± 0.04) × 2RT). This behavior is also reflected in the angular distributions, which are close to a cosine distribution for Ar but slightly narrower, especially for faster atoms, in the case of He. This behavior of He is most likely due to the weak interaction potential between He and the liquid hydrocarbon.

Behavior of gold as hydrogen in certain gold compounds and a very recent experimental report on the noble gas–noble metal interaction in Ar complexes of mixed Au–Ag trimers have motivated us to investigate the effect of hydrogen doping on the Ng–Au (Ng = Ar, Kr, and Xe) bonding through various ab initio based techniques. The calculated results show considerable strengthening of the Ng–Au bond in terms of bond length, bond energy, stretching vibrational frequency, and force constant. Particularly, an exceptional enhancement of Ar–Au bonding strength has been observed in ArAuH2+ species as compared to that in ArAu3+ system, as revealed from the CCSD(T) calculated Ar–Au bond energy value of 32 and 72 kJ mol–1 for ArAu3+ and ArAuH2+, respectively. In the calculated IR spectra, the Ar–Au stretching frequency is blue-shifted by 65% in going from ArAu3+ to ArAuH2+ species. Similar trends have been obtained in the case of all Ar, Kr, and Xe complexes with Ag and Cu trimers. Among all the NgM3–kHk+ complexes (wher...

The discovery of naturally occurring ArH+ in various regions of the interstellar medium has shown the need for more understanding of the reactions that lead to covalently bonded noble gas molecules. The test comes with trying to predict the formation of other small noble gas molecules. Many molecules have been observed in various interstellar environments, which possess the possibility of bonding with noble gases. This work explores how both argon and neon can form bonds to ligands made of these species through quantum chemical computations. Argon and neon are chosen as they are among the most abundant atoms in the universe but are more polarizable than the more common but smaller helium atom. Reactions leading to noble gas molecules are modeled in the gas phase as well as through the adsorbed phase by catalysis with a polycyclic aromatic hydrocarbon (PAH) surface. The adsorption energy of the neutral noble gas atoms to the surface increases as the size of the PAH also increases but this is still less than 10 kcal/mol. It is proposed and supported herein that an incoming molecule can bond with the noble gas atom adsorbed onto the PAH, form a stable structure, and allow the PAH to function as the leaving group. This work shows that the noble gas molecules ArCCH+, ArOH+, ArNH+, and NeCCH+ are not only stable minima on their respective potential energy surfaces but also can be formed in either the gas phase or through PAH adsorption with known or hypothesized interstellar molecules. Most notably, NeCCH+ does not appear to form in the gas phase but could be catalyzed on PAH surfaces. Hence, the interstellar detection of such molecules could also serve as a probe for the observation of interstellar PAHs.

We have investigated noble gas adsorption on graphite surface at constant temperatures using well known two-body potentials. We have also considered quantum effects for Ne-Ne interactions using the FH approximation. We have also distinguished multilayer adsorption at higher pressures (argon and xenon, for example). In order to consider the many-body interactions ( U MB ), a simple and accurate many-body expression has been used with the two-body potentials ( U 2 B ) as: U MB = β U 2 B . The parameter β corrects the difference between the two-body results and the experimental data which not only account for the three-body interactions but also for other effects (such as the three-body repulsions or quantum effects). The effect of this many-body potential for the adsorption system is to decrease the well depth of the potential which makes the potential less attractive. The many-body interaction also decreases the two-body adsorption energy. It is also shown that these effects are greater at higher pressures where the many-body interactions dominate. A modified Wang and Sadus equation (MWS) for consideration of the many-body effects for argon adsorption on graphite has been also proposed. We have also investigated the effect of the many-body interactions on two-body radial distribution functions and self-diffusion coefficients of the different adsorbed molecules.

In this paper, we observed physically adsorbed CO molecules on C60 surface being displaced by impinging noble gas atoms (He, Ne, Ar, Kr), either through a dynamic displacement process or an exothermic replacement process, depending on their adsorption energies. This displacement mechanism could shift from one to the other depending on the surface coverage and temperature. Furthermore, rotational energy of the impinging molecules may also contribute to the dynamic displacement process by supplying additional energy.