Rotational excitation of methylidynium (CH+) by a helium atom at high temperature
K Hammami, LCO Owono, P St�uber�- Astronomy & Astrophysics, 2009 - aanda.org
K Hammami, LCO Owono, P St�uber
Astronomy & Astrophysics, 2009•aanda.orgContext. 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�…
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�…
Context
The Herschel Space Observatory with its high-resolution instrument HIFI on board will observe the CH+ and 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 for J ranging from 0 to 10. Rate coefficients are obtained at high temperatures up to .
aanda.org