Fine-structure excitation of ground-state C+ions by hydrogen atoms

Abstract

Cross sections are computed for the low-energy fine-structure excitation of singly ionized carbon (²P electronic ground state) by atomic hydrogen (²S electronic ground state) in a close-coupling formulation; recent accurate potential energy curves are employed. The effects of rotational coupling and of the fine-structure energy defect are investigated. The excitation cross section is found to be larger than previously computed. The cooling function is calculated for temperatures of astrophysical interest.