15min:

C. TAO, C. MUKARAKATE AND S. A. REID, Department of Chemistry, Marquette University, Milwaukee, WI 53233.

Last year at this meeting, we reported studies of the predissociated, quasilinear B¹A' state of fluorocarbene (CHF and CDF) using a fluorescence dip detected optical-optical double resonance technique via the A¹A'' state. Recently, we have extended these observations to chlorocarbene, measuring OODR spectra of both CH³⁵Cl and CD³⁵Cl. By recording OODR spectra of both isotopomers, we are able to pinpoint the origin of the B¹A' state, while lies near 22 400 cm^-1. In contrast to CHF, the B¹A' origin in chlorocarbene lies below the energetic threshold of the lowest dissociation channel, C(³P) + HCl. However, at higher energies several channels open up, including C-H and C-Cl bond fission, and the OODR spectra show significant lifetime broadening. Trends in the measured linewidths with energy will be discussed.