Fine-structure Excitation of O(3P) Induced by Collisions with Atomic Hydrogen

Abstract

The utility of the far-infrared lines of oxygen as diagnostics of gas outflows and for other applications depends on accurate descriptions of the rate coefficients for excitation (and relaxation) through collisions with electrons and with hydrogen atoms. For O and H collisions, earlier calculations of rate coefficients show discrepancies leading to ambiguity in astrophysical applications. In this note we introduce a methodology that yields consistent sets of rate coefficients for a number of cases. We then apply our method to the O–H system in order to investigate the discrepancies. The present rate coefficients will be of particular interest for modeling observations of astrophysical environments in the far-infrared.