Electronic transition moments for the Herzberg I bands of O2

Abstract

Recently published extensive high-resolution measurements of absolute integrated photoabsorption cross sections for rotational lines of the (ν′ = 4–11, ν″ = 0) bands of the O2 Herzberg I system have been fitted using general rotational line-strength formulae for [Formula: see text] transitions. Good fits were obtained using only three independent electronic transition-moment parameters that accounted for transition strength borrowed from electric-dipole-allowed transitions through spin-orbit and orbit-rotation interactions involving both upper and lower states of the transition. Absolute values of transition-moment parameters have been obtained, corresponding to R-centroids from 1.29 to 1.32 Å (1 Å = 10−10 m). Band oscillator strengths derived from the calculated integrated line strengths are in good agreement with most experimental measurements. Principal electronic matrix elements have been estimated by assuming that strength is borrowed from only two electric-dipole-allowed transitions.