Spectroscopic studies of diatomic noble gas halides. IV. Vibrational and rotational constants for the <i>X</i>, <i>B</i>, and <i>D</i> states of XeF

Abstract

The B→X and D→X systems of XeF are recorded by photographing the emission from the low-pressure Xe*/XeF2 and Ar*/XeF2 reactions. A rotational analysis is obtained for the 1–2 band of B–X, for which isotopic blending is negligible. Vibrational parameters for the X, B, and D states are derived from a direct, weighted least-squares fit of all assignments for both transitions. Rotational parameters are deduced from the vibrational dependence of the band shapes and intensities. Some significant results of this analysis are ReX=2.293 å, ReB=2.631 å, ReD=2.51 Å, ωeX=225 cm−1, ωeB=309.0 cm−1, ωeD=350.1 cm−1, and 𝒟eX=1175 cm−1. The Franck–Condon factors for many of the bands in both systems show a strong rotational dependence, which is to be expected in transitions of this type, for reasons discussed herein.