STATE-TO-STATE PHOTODISSOCIATION OF ORIENTED HF-HCL COMPLEXES - ISOTOPIC AND ISOMERIC EFFECTS

Photofragment angular distributions have been obtained for the vibrati onal predissociation of both isomers of the HF-HCl binary complex. Sta te-selective excitation of the parent complex is carried out using a h igh-resolution F-center laser. To obtain a complete assignment of the data in terms of final state distributions of the fragments, it was ne cessary to both orient the parent molecules in a de electric field and state selectively detect the HF fragments using a second probe laser. The dissociation energy of the HF-HCl isomer is determined to be 642 +/- 2 cm(-1). Dissociation of this complex leads to the production of a upsilon = 1 HCl fragment. The final state distributions for the two isotopomers (Cl-35/Cl-37) are quite different even though the energeti cs associated with these two systems are essentially the same. The ana lysis of the HCl-HF distributions, although more qualitative, suggests that the V-V channel is dynamically blocked by the heavy chlorine ato m, resulting in the production of upsilon = 0 HCl.