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Related papers: Effective collision strengths between Mg I and ele…

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Energy levels, radiative rates (A-values) and lifetimes, calculated with the GRASP code, are reported for an astrophysically important O-like ion Mg~V. Results are presented for transitions among the lowest 86 levels belonging to the…

Atomic Physics · Physics 2016-09-28 K M Aggarwal , F P Keenan

We evaluate various analytical models for the electron-ion energy transfer and compare the results to data from molecular dynamics (MD) simulations. The models tested includes energy transfer via strong binary collisions, Landau-Spitzer…

Plasma Physics · Physics 2014-03-05 J. Vorberger , D. O. Gericke

Iron plays a crucial role in studies of late-type stars. In their atmospheres, Fe I is the minority species and its lines are subject to the departures from LTE. In contrast, one believes that LTE is a realistic approximation for Fe II…

Solar and Stellar Astrophysics · Physics 2019-10-23 Lyudmila Mashonkina , Tatyana Sitnova , Svetlana A. Yakovleva , Andrey K. Belyaev

Data for inelastic processes due to hydrogen atom collisions with iron are needed for accurate modelling of the iron spectrum in late-type stars. Excitation and charge transfer in low-energy Fe+H collisions is studied theoretically using a…

Solar and Stellar Astrophysics · Physics 2018-05-09 P. S. Barklem

The influence of the uncertainties in the rate coefficient data for electron-impact excitation and ionization on non-LTE Li line formation in cool stellar atmospheres is investigated. We examine the electron collision data used in previous…

Solar and Stellar Astrophysics · Physics 2015-05-27 Y. Osorio , P. S. Barklem , K. Lind , M. Asplund

There have been discussions in the recent literature regarding the accuracy of the available electron impact excitation rates (equivalently effective collision strengths $\Upsilon$) for transitions in Be-like ions. In the present paper we…

Atomic Physics · Physics 2016-09-07 K. M. Aggarwal , F. P. Keenan , K. D. Lawson

A close coupling quantum-mechanical calculation is performed for rotational energy transfer in a HD+HD collision at very low energy, down to the ultracold temperatures: $T \sim 10^{-8}$ K. A global six-dimensional H$_2$-H$_2$ potential…

Chemical Physics · Physics 2015-06-03 Renat A. Sultanov , Dennis Guster , S. K. Adhikari

The energy partition in high Mach number collisionless shock waves is central to a wide range of high-energy astrophysical environments. We present a new theoretical model for electron heating that accounts for the energy exchange between…

High Energy Astrophysical Phenomena · Physics 2024-10-22 Arno Vanthieghem , Vasileios Tsiolis , Anatoly Spitkovsky , Yasushi Todo , Kazuhiro Sekiguchi , Frederico Fiuza

Electron-ion interactions play a central role for the energy relaxation processes and ultra-fast structure dynamics in laser-heated matter. The accurate prediction of the electron-ion energy exchange in a transient excited two-temperature…

Other Condensed Matter · Physics 2024-01-17 Jia Zhang , Rui Qin , Wenjun Zhu , Jan Vorberger

We carry out calculations on $M$-changing collisions of NH ($^3\Sigma^-$) molecules in magnetically trappable states using a recently calculated potential energy surface. We show that elastic collision rates are much faster than inelastic…

Chemical Physics · Physics 2015-05-13 Alisdair O. G. Wallis , Jeremy M. Hutson

The analysis of Balmer-dominated optical spectra from non-radiative (adiabatic) SNRs has shown that the ratio of the electron to proton temperature temperature at the blast wave is close to unity at v_s <= 400 km/s, but declines sharply…

Astrophysics · Physics 2009-11-11 Parviz Ghavamian , J. Martin Laming , Cara E. Rakowski

We present the non-local thermodynamic equilibrium (non-LTE) calculations for O I with the updated model atom that includes quantum-mechanical rate coefficients for O I + H I inelastic collisions from the recent study of Barklem (2018). The…

Solar and Stellar Astrophysics · Physics 2018-08-23 Tatyana Sitnova , Lyudmila Mashonkina

Energy levels and radiative rates (A-values) for four types of transitions (E1, E2, M1, and M2) are reported for an astrophysically important Mg-like ion Si~III, whose emission lines have been observed in a variety of plasmas. For the…

Atomic Physics · Physics 2016-11-16 K M Aggarwal

We report an experimental study of quantum conductivity corrections for two-dimensional electron gas in a GaAs/InGaAs/GaAs single and double quantum wells in a wide temperature range (1.8-100) K. We perform a comparison of our experimental…

Mesoscale and Nanoscale Physics · Physics 2019-06-26 S. V. Gudina , Yu. G. Arapov , V. N. Neverov , A. P. Savelyev , S. M. Podgonykh , N. G. Shelushinina , M. V. Yakunin

We consider trasfer-ionization in collisions of fast (3.6 -- 11 MeV/u) protons, alpha-particles and lithium nuclei with helium atoms. There are just a few basic mechanisms contributing to this process which can be grouped into correlated…

Atomic Physics · Physics 2015-06-05 A. B. Voitkiv , X. Ma

An overview of quantum-mechanical methods to generate cross-section data for electron collisions with atoms and molecules is presented. Particular emphasis is placed on the time-independent close-coupling approach, since it is particularly…

Plasma Physics · Physics 2016-10-21 Klaus Bartschat , Jonathan Tennyson , Oleg Zatsarinny

We investigate the non-local thermodynamic equilibrium (NLTE) analysis for \ion{Cu}{1} lines with the updated model atom that includes quantum-mechanical rate coefficients of Cu\,$+$\,H and Cu$^+$\,$+$\,H$^-$ inelastic collisions from the…

Solar and Stellar Astrophysics · Physics 2022-08-31 Xiaodong Xu , Jianrong Shi , Xiaofeng Wang

Rate coefficients for inelastic collisions between Li and H atoms covering all transitions between the asymptotic states Li(2s,2p,3s,3p,3d,4s,4p,4d,4f)+H(1s) and Li^+ +H^- are presented for the temperature range 2000-8000 K based on recent…

Astrophysics · Physics 2009-11-10 P. S. Barklem , A. K. Belyaev , M. Asplund

Data for inelastic processes due to hydrogen atom collisions with manganese and titanium are needed for accurate modeling of the corresponding spectra in late-type stars. In this work excitation and charge transfer in low-energy Mn+H and…

Solar and Stellar Astrophysics · Physics 2020-05-13 Jon Grumer , Paul S. Barklem

We study mutual ionization in collisions between atomic hydrogen and helium at impact velocities near the electronic threshold for this process (determined by the condition that kinetic energy of an equivelocity free electron is…

Atomic Physics · Physics 2015-06-17 S. F. Zhang , X. L. Zhu , A. B. Voitkiv , W. T. Feng , D. L. Guo , Y. Gao , R. T. Zhang , E. L Wang , X. Ma