Stimulated Radiative Association of He and H +

Abstract

The enhancement of the rate coefficient for the radiative association of He and H+ to form HeH+ arising from stimulated emission due to a blackbody radiation field is calculated. The effects on the fractional abundance of HeH+ in the early universe, in supernova ejecta, and in planetary nebulae are small. There may occur some enhancement in the abundance of HeH+ in quasar broad-line clouds.