Rotational Analyses for Selected Bands of the 2 ← X¹ Transition of Cl₂

Abstract

Rotational analyses are presented for selected bands of the 21 (v‘= 1−3) ← X1 (v‘‘ = 0) transition of supersonically cooled Cl2, recorded in fluorescence excitation near λ ≤ 128 nm with a tunable, coherent, and monochromatic vacuum ultraviolet laser generated by four-wave difference mixing in Kr gas. Absolute J-numbering was established in part by spectral simulation. Although the band system is perturbed, the effective rotational constants derived in this work are consistent with theoretical calculations that place the excited two-state equilibrium bond length at ∼2.1 Å.