Fluorescence spectra and kinetics of Cs2

The fluorescence spectra of the A 1Σ+u–X 1Σ+g and a3πu–X 1Σ+g transitions in Cs2 have been measured as a function of temperature and Xe buffer gas density. The observed spectra were normalized to the Cs atomic emission. The Xe density dependence of the normalized fluorescence was used to determine an average formation rate constant for the A 1Σ state of 4.2×10−30 cm6/sec. Using a value of 10−29 cm6/sec for the a 3π formation rate constant, predissociation and quenching rate constants from the a 3π to the x 3Σ were determined to be 2.5×109 sec−1 and 9.8×10−11 cm3/sec. Also, the net collisional transfer rate constant from the A 1Σ to a 3π was 1.5×10−11 cm3/sec. The fluorescence spectra were also used to predict the Cs atomic excited state fraction needed to produce an inversion on the A–X transition. The experimentally inferred value was 11% compared wit a theoretical prediction of 0.25%. This result, coupled with the large loss rates, indicate that Cs2 is not an attractive laser candidate on the A–X transition.