Rotational excitation of methylidynium (CH+) by a helium atom at high temperature
Context. The Herschel Space Observatory with its high-resolution instrument HIFI on board will observe the CH+ $1\rightarrow0$ and $2\rightarrow1$ rotational transitions in a wide range of gas temperatures up to 1000 K. Collisional parameters for such temperatures are thus welcome. Aims. We aim to o...
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Published in | Astronomy and astrophysics (Berlin) Vol. 507; no. 2; pp. 1083 - 1086 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
EDP Sciences
01.11.2009
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Subjects | |
Online Access | Get full text |
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Summary: | Context. The Herschel Space Observatory with its high-resolution instrument HIFI on board will observe the CH+ $1\rightarrow0$ and $2\rightarrow1$ rotational transitions in a wide range of gas temperatures up to 1000 K. Collisional parameters for such temperatures are thus welcome. Aims. We aim to obtain accurate rate coefficients for the collisional excitation of CH+ by He for high gas temperatures. Methods. The ab initio coupled-cluster [CCSD(T)] approximation was used to compute the interaction potential energy. Cross sections are then derived in the close coupling (CC) approach and rate coefficients inferred by averaging these cross sections over a Maxwell-Boltzmann distribution of kinetic energies. Results. Cross sections are calculated up to $10\,000~\mathrm{cm^{-1}}$ for J ranging from 0 to 10. Rate coefficients are obtained at high temperatures up to $2000~\mathrm{K}$. |
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Bibliography: | ark:/67375/80W-87KJPXCR-T istex:C67075D8AB3A6180ECFBCEADDDB5898CD3226872 publisher-ID:aa12663-09 other:2009A%26A...507.1083H ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0004-6361 1432-0746 |
DOI: | 10.1051/0004-6361/200912663 |