Hyperfine excitation of CH and OH radicals by He

被引:7
作者
Marinakis, S. [1 ,2 ]
Kalugina, Y. [3 ,4 ]
Klos, J. [5 ]
Lique, F. [6 ]
机构
[1] Univ East London, Sch Hlth Sport & Biosci, Stratford Campus,Water Lane, London E15 4LZ, England
[2] Queen Mary Univ London, Sch Biol & Chem Sci, Dept Chem & Biochem, Joseph Priestley Bldg,Mile End Rd, London E1 4NS, England
[3] Tomsk State Univ, Dept Opt & Spect, 36 Lenin Av, Tomsk 634050, Russia
[4] Russian Acad Sci, Inst Spect, Fizicheskaya St 5, Moscow 108840, Russia
[5] Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA
[6] Univ Havre, LOMC UMR 6294, CNRS, 25 Rue Philippe Lebon,BP 1123, F-76063 Le Havre, France
来源
ASTRONOMY & ASTROPHYSICS | 2019年 / 629卷
基金
俄罗斯科学基金会;
关键词
molecular processes; ISM: molecules; POTENTIAL-ENERGY SURFACES; INELASTIC-SCATTERING; LAMBDA-DOUBLET; CROSS-SECTIONS; COLLISIONS; MOLECULES; PI;
D O I
10.1051/0004-6361/201936170
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Context. Because of their high reactivity, the CH and OH radicals are of particular interest in astrochemistry. Modeling of CH and OH molecules requires the calculation of accurate radiative Einstein coefficients and rate coefficients for (de)excitation by collisions with the most abundant species such as H-2 and He. Aims. The present paper focuses on the calculation of inelastic rate coefficients among the lowest OH/CH hyperfine levels in their ground vibrational state induced by collisions with He atoms. Methods. Calculations of hyperfine (de)excitation of CH/OH by He were performed using the close-coupling and recoupling methods from the most recent ab initio potential energy surfaces. Results. Cross sections for transitions among the 60 and 56 lowest hyperfine levels of CH and OH, respectively, were calculated for collision energies up to 2500 cm(-1). These cross-sections were used to calculate the rate coefficients for temperatures between 10 and 300 K. A propensity rule for transitions with Delta F = Delta j was observed. Conclusions. The new rate coefficients will help significantly in interpreting the CH/OH spectroscopic data observed with current and future telescopes, and help to accurately describe the OH masers and the hyperfine anomalies in CH emission spectra.
引用
收藏
页数:5
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