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State‐to‐state scattering studies of vibrationally excited molecules in the cold regime extend inelastic scattering investigations into a new territory. Here, we present differential cross‐sections for superelastic scattering of spin‐orbit excited nitric oxide (NO) (v = 10, Ω = 1.5, j = 1.5) with argon near 1 K utilizing our recently developed near‐copropagating beam technique, and compare these to quantum scattering calculations on coupled cluster and multi‐reference potential energy surfaces. At these collision energies, the scattering is mainly governed by resonances and provides a platform to assess the accuracy of the attractive part of the difference potential for the NO–Ar system, which has remained untested. Quantum scattering calculations for such inelastic processes on high‐quality potential energy surfaces at thermal energies have largely been successful at reproducing the key features of experimental results, but cold spin‐orbit changing collisions are shown to test the limits of the current theoretical state‐of‐the‐art. The experimental results clearly exhibit backscattering centered around 3.5 cm−1 collision energy suggesting a scattering resonance; such resonances have never been detected for the well‐studied NO–Ar system. A partial wave analysis based on a multireference potential energy surface suggests the enhanced backscattering arises from overlapping resonances associated with the highest partial wave contributions. Key points We have achieved state‐to‐state spin‐orbit changing collisions of highly vibrationally excited NO with Ar near 1 K utilizing the near‐copropagating beam technique. The experiment reveals the influence of quantum scattering resonances for the well‐studied NO–Ar system for the first time. The results are found to challenge the current theoretical state‐of‐the‐art.

Interaction potentials were obtained by the density functional theory (DFT) and nuclear stopping powers (NSP) were calculated for 48 systems in the energy range above 10 eV. It was shown that NSP calculated using the DFT potentials in the collision energy range of 10–1000 eV give more accurate values comparing with the SRIM data, obtained data differs from SRIM data by 15–70%. The presence of a potential well leads to the emergence of an additional NSP peak at low energies. Comparison of classical calculations of the transport cross section with semiclassical ones showed their identity at energies of up to 1 eV. The criterion for the applicability of classical calculations for the transport cross section and NSP cross sections is the condition l>1 (l is the angular momentum). The importance of including multichannel scattering in NSP calculations was demonstrated, for the case of energies below 20 eV.

Feshbach resonances in D + HD(v = 1, j = 0) reaction are studied by using the time-independent quantum method. The integral cross section (ICS) results present three Feshbach resonance peaks, which are different from H + HD(v = 1, j = 0) reaction dominated by only one peak. These resonances are attributed to coupling with adiabatic effective potentials of D + HD(v = 1, j = 1) reaction, and the most obvious peak is contributed by J = 1 at 83.16 cm-1 collision energy. For J = 0 and 2, the resonances are related with the same L partial wave and present a double-peak structure in total ICS. The characteristics of product angular distribution show that the resonance of J = 1 is long-lived, while the lifetimes are relatively shorter for the resonance of J = 0 and 2.

Nitric oxide is an open-shell molecule abundantly detected in the interstellar medium. A precise modelling of its radiative and collisional processes opens the path to a precise estimate of its abundance. We present here the first rate coefficients for fine and hyperfine (de-)excitation of NO by collisions with the most ubiquitous collision partner in the interstellar medium, para-H2 hydrogen molecules, using a recently developed accurate interaction potential. We report quantum scattering calculations for transitions involving the first 74 fine levels and the corresponding 442 hyperfine levels belonging to both F1 and F2 spin–orbit manifolds. To do so, we have calculated cross-sections by means of the quantum mechanical close-coupling approach up to 1000 cm−1 of total energy and rate coefficients from 5 to 100 K. Propensity rules are discussed and the new NO–H2 rates are compared to those available in the literature, based on scaled NO–He rates. Large differences are observed between the two sets of rate coefficients, and this comparison shows that the new collision rates must be used in interpreting NO emission lines. We also examined the effect of these new rates on the NO excitation in cold clouds by performing radiative transfer calculations of the excitation and brightness temperatures for the two NO lines at 150.176 and 250.4368 GHz. This shows that the local thermodynamic equilibrium is not fulfilled for this species for typical conditions. We expect the use of the rates presented in this study to improve the constraints on the abundance of NO.

The fine and hyperfine resolved state-to-state rate coefficients for the rotational (de)excitation of C3N by collision with helium are computed. To this aim a 2D potential energy surface is calculated for this system. The recoupling method is used to obtain the fine and hyperfine structure resolved rate coefficients from spin-free close-coupling calculations. These results are compared with those given by the infinite-order sudden approximation and the M-randomizing limit. General propensity rules for the transitions are also found and analysed.

Collisions of ultrarelativistic electron beams are considered using full-scale 3D particle-in-cell simulation. In this process, the particles can be affected by the superintense fields of the counterpropagating beam, and the interaction can pass to the regime of nonperturbative quantum electrodynamics. In this experimentally unexplored regime, the emission of photons and the production of electron – positron pairs are extremely probable processes. It is shown that due to the transverse displacement of the beams and an increase in the number of particles located in the region of the field maximum, it is possible to increase the yield of both photons and electron – positron pairs.

We present a method for the construction of a one-adjustable-parameter empirical model for the induced dipole moment. The method is based on classical physics principles and relies on the first three spectral moments of the collision-induced absorption spectra at various temperatures and new interaction potentials. In this work it is applied to the spectra of He-Ar mixtures. Our values are in good agreement with the available ab initio data. The profiles calculated with these models at various temperatures are in excellent agreement with experiment.

For accurate electron density diagnostics of plasma, the spectral diagnostics for four-level system instead of three-level system by collision excitation model are investigated. Taking the first fo...

In this paper presents the investigation of the surface Al2O3 by ion scattering spectroscopy. The trajectory of small angle scattered ions calculated by the method of binary collision approximation. It was found dependence of inelastic energy loss and trajectories of scattered ions. The value of inelastic energy loss scattered ions almost depend to the angle of incidence and the geometrical parameters of surface semichannels.

Vibrational energy transfer of a polyatomic molecule upon collision at a solid surface is of fundamental importance in surface chemistry. As a full quantum treatment of this process is extremely ch...

In the present study, we have investigated scattering of an electron by hydrogen atoms in the presence of the elliptical polarized laser field. We have discussed the polarization effect of laser field on hydrogen atom and effect of the resulted polarized potential on differential scattering cross-section is studied. We assume the scattered electrons having kinetic energy (~3000 eV) and laser field of moderate field strength because it is permitted to treat the scattering process in first Born approximation and the scattering electron was described by Volkov wave function. We found that the differential scattering cross-section area increases with the increase of the kinetic energy of the incident electron and there is no effect of changing the value of polarizing angle on the differential cross-section with kinetic energy. We observed that differential scattering cross-section in elliptical polarization in the high energy region depends upon the laser intensity and the incident energy for a linearly polarized field.

The C5S molecule is the largest member of the series of sulphur-containing carbon chains CnS observed in space. Given the lack of data concerning this molecule, we computed rate coefficients of C5S(1Σ+) induced by collision with He. These rates are obtained for thermal temperature below 100 K by mean of a new two-dimensional potential energy surface (PES) calculated with the explicit correlated coupled cluster with single, double, and pertubative triple excitation (ccsd(t)-f12) ab initio approach and the aug-cc-pVTZ basis sets. The C5S–He PES presents three minimums of −59.726, −55.355, and −36.506 cm−1 below its dissociation limit. Using this PES, the integral cross-sections are performed in the close-coupling (CC) and coupled-state (CS) quantum time independent formalisms for $E_\mathrm{ c}\le 500 \, \mathrm{ cm}^{-1}$ and J ≤ 13 (for CC) and J ≤ 50 (for CS). By averaging these cross-sections we obtained the downward rate coefficients. The new collisional data are used to simulate the excitation of C5S in the circumstellar gas. We obtain the excitation and brightness temperatures of the four lines observed towards the IRC+10216 which confirms the necessity of using radiative transfer calculations to accurately determine C5S abundance since the local thermodynamic equilibrium conditions are not fulfilled. The new collisional data should help to estimate the abundance of C5S in several interstellar regions.

In the paper, experimental results concerning the dynamics of the counter interaction of high-energy plasma flows in a magnetic field with an induction of up to 2 T are presented and discussed. Plasma flows with velocities (2–4) × 107 cm/s, ion density (2–4) × 1015 cm–3, and energy content of 70–100 kJ were formed by two electrodynamic coaxial accelerators with pulsed gas injection. Nitrogen and neon, as well as their mixtures with deuterium, were used as working gases. A description of the 2MK-200 facility, where the experiments were carried out, and diagnostic equipment are presented. Experimental results obtained in various operating modes of the facility are reported and discussed.

A simple way of estimating the probability of helium ions He+ surviving when reflected from different metal surfaces is described that employs modeling with the SCATTER and TRIM binary collision codes. The probability of reflected helium ions surviving is estimated from their energy spectra, in the form of the ratio of their areas. The dependences of the probability of He+ ions reflected from Cu and Al surviving on the reciprocal perpendicular velocity are calculated, and the characteristic velocity of an electron migrating from a metal to an incident ion is estimated.

Ion-molecule charge-exchange reactions Ar+ + CO → Ar + CO+ at the center-of-mass collision energies of 4.40, 6.40, and 8.39 eV are investigated using ion velocity map imaging technique. Although multiple electronically excited states of CO+ are accessed, the population of CO+ at the A2Π state is predominant in the present collision-energy range. In contrast to our previous study for NO, but similar to the case of O2, the forward-scattered CO+ yields show a broader angular distribution at the higher collision energy. Typically, the Franck-Condon-region charge transfer, energy resonant charge transfer, and intimate collision are three different mechanisms in which the intimate collision experiences an intermediate complex, and this mechanism usually plays an essential role in the thermal-energy reactions. However, the present observations indicate that this mechanism, concerning the intermediate (Ar-CO)+, is still of utmost importance in a relatively high collision-energy range.

The reaction of chlorine atom Cl(2P) (Cl(2P3/2) and Cl∗(2P1/2)) with D2 was investigated at collision energy from 4.5 kcal/mol to 6.5 kcal/mol with a high-resolution crossed molecular beam apparatus using the technique of D-atom Rydberg tagging detection. The contribution from the spin-orbit excited reaction Cl∗(2P1/2)+D2, which is prohibited by Born-Oppenheimer (BO) approximation, was observed. Collision-energy dependence of differential cross sections (DCSs) near the backward scattering direction was measured. The BO-forbidden reaction Cl∗+D2 was found to be dominant at lower collision energy. As collision energy increases, reactivity of BO-allowed reaction Cl+D2 increases much faster than that of BO-forbidden reaction and becomes dominant at higher collision energy. Our experiment indicates that the additional energy of spin-orbit excitation in Cl∗ facilitates BO-forbidden reaction to pass through the barrier at lower collision energy, while BO approximation is still valid at collision energy near and above the reaction barrier. This tendency of reactivity of Cl/Cl∗+D2 is similar to the isotopic reaction of Cl/Cl∗+H2.

The first tentative detection of the nitrosylium ion (NO+) in the interstellar medium (ISM) was reported just a few years ago. The application of non-local thermal equilibrium models requires the knowledge of the collisional rate coefficients with the most common colliders in the ISM (e.g. He, H, H2, and e). The main goals of this paper are to study the collision of the NO+ molecule with para-H2 (j = 0) and report the rate coefficients for the lower rotational states of NO+. A large set of ab initio energies was computed at the CCSD(T)/aug-cc-pV5Z level of theory. A new potential energy surface averaged over the H2 orientations was then fitted using a reproducing kernel Hilbert space procedure. The state-to-state cross-sections of NO++para-H2 (j = 0) for the first 18 rotational levels were computed using the close-coupling method. The rotational rate coefficients of this system were compared with those for NO++He, and a different propensity rule was found. Furthermore, the hyperfine rate coefficients were also calculated using the infinite-order-sudden scaling procedure.

An advanced relativistic energy approach combined with a scattering theory is used to calculate the electron-collision excitation cross-sections, collision strengths for a number of multicharged ions. The relativistic many-body perturbation theory is used alongside the gauge-invariant scheme to generate an optimal Dirac-Kohn-Sham- Debye-Huckel one-electron representation. The results of relativistic calculation (taking into account the exchange and correlation corrections) of the electron collision cross-sections (strengths) of excitation of the transition between the fine-structure levels (2P 3/2 - 2P 1/ 2 ) of the ground state of F-like ions with Z = 19-26 and of the [2s 2 1 S-(2s2p 1 Р)] transition in the В-like O 4+ are presented and analysed.

The internuclear distance (R) dependence of the correlated electron dynamics in strong-field nonsequential double ionization (NSDI) of parallel aligned diatomic molecules has been investigated. Res...

Emission excitation cross sections are recorded for collisions between Xe2+ + O2 and O+ + Xe over a collision energy range of approximately 2 to 900 eV in the center-of-mass (Ecm) frame. Emissive products of the O+ + Xe reaction are examined in the 700–1000 nm optical range and include neutral atomic oxygen emissions and neutral xenon emissions. Atomic emission products of the O+ + Xe collision appear to have measureable cross sections near Ecm = 14 eV and increase in intensity until about Ecm = 60 eV where they remain approximately constant for the remainder of the measured collision energies. For the Xe2+ + O2 collision system, O2+ charge transfer products are measured through fluorescence of the O2+(A–X) and (b–a) manifolds over the 200–850 nm window. Total cross sections for both manifolds do not vary beyond the experimental precision at all measured energies. Vibrational populations are derived from a fitting of the experimental data. The populations are found to deviate from a Franck–Condon distribution at all collision energies and appear to be well-modeled within a multi-channel Landau–Zener framework over the collision energy range measured.

© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim In order to study collisions between ions and neutrals, a new Guided Ion Beam (GIB) apparatus, called NOVion, has been assembled and tested. The primary purpose of this instrument is to measure absolute cross sections at energies relevant for technical or inter- and circumstellar plasmas. New and improved results are presented for forming H3+ in collisions of H2+ with H2. Between 0.1 eV and 2 eV, our measured effective cross sections are in good overall agreement with most previous measurements. However, at higher energies, our results do not show the steep decline, recommended in the standard literature. After critical evaluation of all experimental and theoretical data, a new analytical function is proposed, describing properly the dependence of the title reaction on the collision energy up to 10 eV.

Neon was applied as a collision gas in a collision/reaction cell of ICP-QMS, since it has a very high ionization potential and does not react with other elements in a collision/reaction cell as well as He. Neon was more effective as a collision gas than He even under the same conditions which had been optimized for He and much more effective under the optimum conditions for each collision gas, because the Ne atom is larger and heavier than the He atom. To evaluate the usefulness of Ne as a collision gas, it was applied to the determination of metallic elements in a river water CRM. The results obtained were in good agreement with its certified values. We also proposed a “cell gas index” which assesses the effectiveness of He, H2, Ne, Ar, O2, N2, Kr, and Xe as a collision/reaction gas considering their chemical and physical parameters.

Inelastic collisions and elementary chemical reactions proceeding through the formation and subsequent decay of an intermediate collision complex, with an associated deep well on the potential energy surface, pose a challenge for accurate fully quantum mechanical approaches, such as the close-coupling method. In this study, we report on the theoretical prediction of temperature-dependent state-to-state rate coefficients for these complex-mode processes, using a statistical quantum method. This statistical adiabatic channel model is benchmarked by a direct comparison using accurate rate coefficients from the literature for a number of systems (H2 + H+, HD + H+, SH+ + H, and CH+ + H) of interest in astrochemistry and astrophysics. For all of the systems considered, an error of less than factor 2 was found, at least for the dominant transitions and at low temperatures, which is sufficiently accurate for applications in the above mentioned disciplines., Comment: 11 pages, 5 figures

Collision of asymmetric nuclei like Cu+Au provides the means to study hard probes in different collision geometry compared to collisions of symmetric nuclei like Cu+Cu and Au+Au. A systematic study of the production of high transverse momentum particles and jets in systems with different geometry may provide information about the path-length dependence of energy loss in the medium. The PHENIX experiment has measured the transverse momentum distributions and the nuclear modification factors, R A A of jets and leading particles, such as π 0 mesons, in Cu+Au collisions at s N N = 200 GeV . The jets are reconstructed with the anti- k T clustering algorithm with a distance parameter of R = 0.2 , chosen to minimize the contribution of the underlying event. The R A A measurements in Cu+Au collisions are presented as a function of p T and centrality and compared to theoretical calculations.

We reinvestigate a key process in electron-atom collision physics, the elastic scattering of electrons from helium atoms. Specifically, results from a special-purpose relativistic polarized-orbital method, which is designed to treat elastic scattering only, are compared with those from a very extensive, fully ab initio, general-purpose B-spline R-matrix (close-coupling) code.

We study the collision of a kink and an antikink in the double sine-Gordon model with and without the excited vibrational mode. In the latter case, we find that there is a limited range of the parameters where the resonance windows exist, despite the existence of a vibrational mode. Still, when the vibrational mode is initially excited, its energy can turn into translational energy after the collision. This creates one-bounce as well as a rich structure of higher-bounce resonance windows that depend on the wobbling phase being in or out of phase at the collision and the wobbling amplitude being sufficiently large. When the vibrational mode is excited, the modified structure of one-bounce windows is observed in the whole range of the model's parameters, and the resonant interval with higher-bounce windows gradually increases with the wobbling amplitude. We estimated the center of the one-bounce windows using a simple analytical approximation for the wobbling evolution. The kinks' final wobbling frequency is Lorentz contracted, which is simply derived from our equations. We also report that the maximum energy density value always has a smooth behavior in the resonance windows., 19 pages, 12 figuers

Long-distance charge-dipole attraction between atomic ion and randomly oriented polar molecule potentially makes the molecular orientation, which profoundly influences the products' kinetics of collisional reaction. Using the three-dimensional ion velocity map imaging technique, here we report a collision-energy dependent stereodynamics of dissociative charge exchange reaction Ar+ + CO → Ar + O + C+ in a range of 7.46-9.97 eV. At the lowest collision energy, the most C+ products are forward-scattered and are along the collision axis and are attributed to three different dissociation channels including the predominant one experiencing the rotating intermediate ArC+. At the high collision energies, the remarkably diffusive distribution of C+ arises from the prompt dissociation of the rebounded CO+. The different dynamic processes arising from the nearly collinear collision are elaborated explicitly on the basis of the data analyses using the Doppler kinetics models.

We present state-selective electron capture cross sections in collision between Be4+ and ground state hydrogen atom. The n- and nl-selective electron capture cross sections are calculated by a three-body classical trajectory Monte Carlo method (CTMC) and by a classical simulation schema mimicking quantum features of the collision system. The quantum behavior is taken into account with the correction term in the Hamiltonian as was proposed by Kirschbaum and Wilets (C. L. Kirschbaun, and L. Wilet, Phys. Rev. A 21, 834 (1980)). Calculations are carried out in the projectile energy range of 1-1000 keV/amu. We found that our model for Be4++ H(1s) system remarkably improves the obtained state-selective electron capture cross sections, especially at lower projectile energies. Our results are very close and are in good agreement with the previously obtained quantum-mechanical results. Moreover our model with simplicity can time efficiently carry out simulations where maybe the quantum mechanical ones become complicated, therefore, our model should be an alternative way to calculate accurate cross sections and maybe can replace the quantum-mechanical methods.

The dependences of potential energies E(R) for 48 states of the Ar*–He collision complex on the interatomic distance R were obtained using multiconfigurational methods of quantum mechanics with consideration of spin–orbit coupling with active space (6, 7). The values E(R ≥ 10 A) are in good agreement, with an accuracy of 10–200 cm–1 (0.05–0.3%), with energies of Ar atom states.

By performing numerical calculations of the quasi-two-dimensional GP equation, the dynamical generation and evolution of vortex excitations under collision between a superflowing ring-shaped BEC and a centered static BEC are investigated. We study the collision between a superflowing ring-shaped BEC and a static centered BEC. Symmetrically positioned singly quantized vortices can be created and their time evolution mainly depends on the atomic interactions.

Cyanides/isocyanides are the most common metal-containing molecules in interstellar medium. In this work, quantum scattering calculations were carried out to determine the rotational (de-)excitation cross-sections of the most stable form of the sodium cyanide molecule, t-NaCN, in collision with the helium atom. Rate coefficients for the first 43 rotational levels (up to ${j_{{K_a}{K_c}}}$ = 63,3) of NaCN were determined for kinetic temperatures ranging from 1 to 30 K. Prior to that, we constructed a new three-dimensional potential energy surface (3D-PES) for the t-NaCN–He interacting system. These electronic structure computations are done at the CCSD(T)-F12/aug-cc-pVTZ level of theory. Computations show the dominance of Δj = ΔKc = −1 transitions, which is related to the dissymmetric shape of the t-NaCN–He 3D-PES. The NaCN–He rate coefficients are of the same order of magnitude (∼10−11 cm3.s−1) as those of other metal CN-containing molecules such as MgCN and AlCN in collision with He. This work is a contribution for understanding and modelling the abundances and chemistry of nitriles in astrophysical media.

We calculate the strongly intensive variables Σ and Δ that suppress trivial volume fluctuations and are constructed for the charged particle multiplicity n and the total transverse momentum Pt in a modified multipomeron exchange approach for proton-proton interactions in the range of collision energies attainable with the SPS and LHC accelerators. In this approach, the interaction between the color quark-gluon strings formed from cut pomerons are effectively taken into account; in this case, the role of these interactions increases as the collision energy increases. The inequalities Σ(Pt, n) > 1 and Δ(Pt, n) < 1, which agree with the experimental data, are the main result of the calculations for energies attainable at the SPS. We show that as the energy increases, Σ(Pt, n) behaves nonmonotonically and Δ(Pt, n) increases.

The influence of electrons trapped between the magnetic mirror and the Debye sheath on the potential profile in the expander of an open trap is considered. A numerical model is developed to calculate the electron distribution function in the self-consistent electrostatic potential. Passing electrons are assumed to be collisionless, while the distribution function of trapped electrons is calculated by solving the bounce-averaged kinetic equation with the Landau collision integral. The self-consistent profile of the potential is obtained. The solution is shown to agree well with Ryutov’s semi-analytical model.

Recent progress in studying the breakthrough phase (BTP) of the attachment process in lightning and long sparks is reviewed. The main focus is on the new insights gained from recent observations for 3 types of electric discharges: natural lightning (Nag et al., 2012; Tran and Rakov, 2017a,c), rocket-and-wire triggered lightning (Howard et al., 2010; Hill et al., 2016), and long sparks (Kostinskiy et al., 2016). The BTP (also known as the final jump) starts when the poorly-conducting streamer zones, developing ahead of the hot channels of negative downward leader (DL) and positive upward connecting leader (UCL), come in contact and a common streamer zone (CSZ) is formed. The beginning of BTP (establishment of CSZ) is usually marked by an abrupt current rise, a burst of dE/dt pulses (referred to as leader burst or LB), and hard X-ray emission. During the BTP, hot channels of both DL and UCL extend toward each other inside the CSZ, resulting in its shrinking, until the high-impedance CSZ is eliminated and low-impedance connection of DL to the grounded object is established. The process of bridging of CSZ by hot leader channels is accompanied by the formation of slow front (SF) in the channel current and in electric and magnetic field waveforms at both close and far distances from the channel. Attempted or relatively weak hot-channel connections producing current surges and associated field pulses superimposed on the SF (SF pulses) can occur. The SF lasts some microseconds and ends at the onset of the submicrosecond-scale fast transition (FT), which signifies the end of BTP. During the BTP, the current rises from the UCL level of the order of tens to hundreds of amperes to about 50% of the overall (SF + FT) current peak, which is of the order of tens of kiloamperes (for negative first strokes). This two orders of magnitude current rise during the BTP occurs before the collision of hot leader channels inside the CSZ; that is, before the onset of return stroke proper.

The kinetics of rotational inelastic NH3-NH3 collisions are recorded using pump-probe experiments, carried out with a K-band waveguide chirped pulse Fourier transform microwave spectrometer, in which the population of one inversion doublet is altered by the pump pulse. Due to self-collisions, the resulting deviation from equilibrium propagates to other states and, thus, can be interrogated by probe pulses as a function of the pump-probe delay time. A clear hierarchy of the state-to-state collision processes is found and subsequently translated into propensity rules. State-to-state rate coefficients are estimated, first via an analysis of the kinetics, and then more robustly and accurately derived from the pressure-dependent measurements using a global fitting procedure.

In one of the papers, El-Maaref et al. [J. Elect. Spectrosc. Related Phen. 215 (2017) 22] have reported results for energy levels, oscillator strengths (f-values), radiative rates (A-values), collision strengths (Ω), and excitation rates for transitions in S-like Mn X. However, except for energy levels their results are restricted to only a few transitions and hence have limited application. Furthermore, most of their results have scope for improvement, but for Ω are not correct as these have been found to be overestimated by an order of magnitude. In this comment we discuss the discrepancies and deficiencies of their results and recommend that a fresh calculation should be performed for this ion.

The stereodynamics of the reaction H(2S) + NH (v = 0, 1, 2, 3; j = 0) → N(4S) + H2 are studied using the quasi-classical trajectory method on a double many-body expansion potential energy s...

The reaction dynamics of Penning ionisation of a polycyclic aromatic hydrocarbon (PAH), naphthalene C10H8, in collision with the metastable He*(23S) atom is studied by classical trajectory calculations using an approximate interaction potential energy surface between He* and the molecule, which is constructed based on ab initio calculations for the isovalent Li + C10H8 system. The ionisation width (rate) around the molecular surface are obtained from overlap integrals of the He 1s orbital and the molecular orbital. The calculated collision energy dependences of partial Penning ionisation cross sections (CEDPICS) in the range 50–500 meV at 300 K have reproduced the experimental results semi-quantitatively. The opacity functions, which represent the reaction probability with respect to the impact parameter b, are discussed in connection with collision energy, interaction with He* and the exterior electron density of molecular orbitals. They indicate that the collisional ionisations of C10H8 can be classified into three types: π electron ionisations with negative collision energy dependences which are predominantly determined by attractive interaction with He*; σ orbitals ionisations of the hardcore type; σ orbital ionisations which reflect interaction potentials around CH bonds. The critical impact parameters bc become larger with increasing collision energy due to the centrifugal barrier.

The linear features and phenomena concerning head-on collision between the two ion acoustic solitary waves are investigated considering the multi-component plasma system comprising singly charged c...

Energy levels and transition rates for electric-dipole, electric-quadrupole, magnetic-dipole, and magnetic-quadrupole transitions among the levels arising from the n ≤ 5 configurations in Al-like Cu XVII are calculated respectively by two state-of-the-art methods, namely, the Multi-Configuration Dirac–Hartree–Fock approach and the second-order many-body perturbation theory. Our results are compared with available experimental and other theoretical values. In addition, effective collision strengths of direct excitation between these levels are provided using the distorted wave approximation. Several line pairs are pointed out that might be useful for density diagnostics.

Modified Complex Robert-Bonamy (MCRB) calculations of the half-width, line shift, and their temperature dependence were made for the H2O-N2 collision system. Several methods, intercomparison of the measured line shape data and the Group of Transitions methods, were tested to select a set of measured half-widths and line shifts with small uncertainty. The atom-atom parameters of the intermolecular potential were refined by matching the MCRB calculation results to those of the selected transitions. Transitions for the rotation and ν2 bands were selected from the HITRAN2016 database [Gordon et al. JQSRT 203, 3, 2017] and MCRB calculations employing the final intermolecular potential were made for these transitions. The calculations were made at 13 temperatures between 200 and 3000 K and the temperature dependence of the half-width and line shift determined. The MCRB data were compared with the measurement database. The comparison of the half-widths gives average percent differences of 4.71% and −2.74% and the comparison of the line shifts gives average deviations of −0.00166 and −0.000547 cm−1 atm−1 for the rotation and ν2 bands, respectively. A file of the final results is available as supplemental data and the corresponding author's website.

The phenomena occurring under head-on collision of ion-acoustic solitary waves in collisionless plasma consisting of positive and negative ions and electrons obeying the Boltzmann distribution are considered. Using particle-in-cell simulations, it is shown that large-amplitude compressive ion-acoustic solitary waves do not preserve their identity after the collision. Their amplitudes decrease and their shapes change. It is shown that the collision is accompanied by the generation of fast positive ions the velocity of which can exceed more than threefold the speed of sound. In addition, the collision is accompanied by the trapping of negative ions by the field of ion-acoustic solitary waves formed after the collision.

This paper represents a contribution toward finding a complete set of electron collision cross sections for the methane molecule by revising all of the collision cross sections and adding the partial collision cross sections data relating to dissociation by electron impact. For the latter, there are no available measurements data for each channel of dissociation and no validated recommended data for use in the modeling, although these data are very important in order to determine different species in a methane plasma. The rate coefficients of the partial dissociative collisions into neutrals and the partial ionization collisions are also calculated, and when fitted, these can be used as input for fluid models. This paper is concluded by the validation of our set of data through a comparison between the transport coefficients calculated by using our data and the measurements of the transport coefficients that already exist in the literature.

The ro-vibrational transitions of NaH are crucially needed for the control of photo-association processes resulting from its formation and for accurately modeling the NaH abundance in space. In this work, we constructed new PESs of the NaH-He system. The potentials were computed at the CCSD(T)-F12/ cc-pVTZ level of theory. Each of the PESs presents two local minima. From these PESs, we calculated rotational cross sections of NaH induced by collision with He using the close coupling approach. These cross sections were then averaged at low temperature to obtain the collisional rates. The propensity rules favorite odd Δ j transitions. The collisional rates presented in this paper may be crucial for the astrophysical community. The three dimensional PES can be used later to compute ro-vibrational quenching rate coefficients to interpret the NaH collisional interaction with laser-cooled atoms.