The broadening of d-f and f-d transitions by collisions with neutral hydrogen atoms

Abstract

The theory of Anstee & O'Mara for the broadening of spectral lines owing to collisions by neutral hydrogen atoms is extended to d-f and f-d transitions of neutral atoms. Width cross-sections are tabulated against effective principal quantum numbers for the upper and lower states of the transition, for a relative collision velocity of 104 ms-1. The cross-sections are fitted to a variation with velocity of v-α, and results for the velocity parameter a are similarly tabulated. The data are tested by application to d-f spectral lines in the solar spectrum. The derived abundances are consistent with those for meteorites.