15min:

C. TAO, C. MUKARAKATE AND S. A. REID, Department of Chemistry, Marquette University, Milwaukee, WI 53233; T. W. SCHMIDT AND S. H. KABLE, School of Chemistry, University of Sydney, NSW 2006, Australia.

We have recently observed transitions to the predissociated, quasilinear B¹A' state of a halocarbene, CHF, using a fluorescence dip detected optical-optical double resonance technique via the A¹A'' state. By exciting selected rotational levels in intermediate states belonging to the progressions 2₀ⁿ, 1₀¹2₀ⁿ, and 2₀ⁿ3₀¹, a variety of B¹A' state levels have been observed, extending to an energy of 7000 cm^-1 above the B¹A' state origin. In this talk, we will focus on the dynamics of the B¹A' state. All of the observed lines are predissociated, as evidenced by Lorentzian lineshapes, and the linewidths increase with increasing energy. A pronounced mode specificity is observed; levels containing CF stretching excitation dissociate more rapidly than nearly isoenergetic bending levels. The implications of these results for the dissociation mechanism will be emphasized.