RADIATIVE LIFETIME MEASUREMENTS FOR THE $B ^{3}\Pi (0^{+})$ STATE OF CHLORINE MONOFLUORIDE

(1). M.A.A. Clyne and E. Martinez, J.C.S. Faraday Trans. II 76, 1275 (1980). Address of van de Burgt and Heaven: Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616.Author Institution:Radiative lifetime measuremetns for the $B^{3}\Pi (0^{+})$ state of CIF have been made for the first time. Pulsed laser excitation was used to excite a single ro-vibrational level $(v^{\prime} = 5, J^{\prime} = 16)$ of the B state, and fluorescence decay curves were recorded for CIF pressures ranging from 0.001 to 0.2 torr. The resulting Stern-Volmer plot defined a radiative lifetime of $1.3\pm .3 ms$ and a deactivation rate constant of $2.8\times 10^{-11} cm^{3} molecule^{-1} 8^{-1}$. The observed radiative lifetime is in good agreement with the expected value of 1-3 ms, based on an extrapolation of data for the other $interhalogens.^{1}$ The deactivation rate constant is most probably influenced by the effects of vibrational energy transfer. Relaxation red-shifts the fluorescence spectrum and this diminishes the efficiency with which the emission is detected by the photomultiplier. Therefore, the measured deactivation rate constant should be regarded as an upper limit for the electronic self quenching rate constant. Further measurements are in progress, and a summary of the results will be presented. Work supported by AFOSR under grant 85-0210