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

Abstract

The collisional broadening theory of Anstee & O'Mara for s-p and p-s transitions by collisions with atomic hydrogen is extended to p-d and d-p transitions. Width cross-sections for collisional broadening of atomic lines corresponding to p-d and d-p transitions by neutral hydrogen atoms are tabulated as a function of effective principal quantum numbers for the upper and lower states, for a relative velocity of 10 ms. The cross-sections vary with velocity as v, and results for the parameter α are similarly tabulated. The cross-sections are tested by application to synthesis of suitable strong solar lines. The derived abundances are consistent with meteoritic values.