Radiative charge transfer in collisions of C with He⁺

Abstract

Radiative charge exchange collisions between a carbon atom C( 3 P ) and a helium ion He + ( 2 S), both in their ground state, are investigated theoretically. Detailed quantum chemistry calculations are carried out to obtain potential energy curves and transition dipole matrix elements for doublet and quartet molecular states of the HeC + cation. Radiative charge transfer cross sections and rate coefficients are calculated and are found at thermal and lower energies to be large compared to those for direct charge transfer. The present results might be applicable to modelling the complex interplay of [C ii] (or C + ), C, and CO at the boundaries of interstellar photon dominated regions (PDRs) and in xray dominated regions (XDRs), where the abundance of He + affects the abundance of CO.

Radiative association of C(3P) and H+: triplet states

“…4. For comparison, we calculated the radiative decay cross sections using the distorted wave optical potential approach as detailed by Babb & McLaughlin (2017). The present results for radiative decay generally agree with those of Stancil et al (1998a); being about a factor two larger than theirs at 10 −4 eV, though gradually becoming comparable for increasing energies, and being equal for energies above 0.1 eV.…”