PHOTODISSOCIATION DYNAMICS OF OCLO AT 157 NM

Photodissociation of OClO at 157.6 nm:excitation has been investigated using the photofragment translational spectroscopic technique; Two di stinctive chemical dissociation channels have been observed; one is th e binary dissociation process, OClO+hv-->ClO+O; the other one is the,t riple dissociation process, OClO+hv-->Cl+O+O. The branching ratio of t he binary dissociation channel to the triple dissociation channel is: determined to be 0.59:0.41. Bimodal;vibrational distribution of the Cl O product has been observed for the OClO-->ClO(X (II)-I-2)+O(P-3, D-1) channel, implying that two distinctive dissociation routes possibly e xist in the binary dissociation process. The bimodal distribution is l ikely caused by the two dissociation pathways from two excited electro nic states:the D((2)A(1)) and E(B-2(1)) states of OClO. These argument s are further supported by the results of the anisotropy parameter mea surements or the binary dissociation channels. Experimental; results a lso show that the OClO+hv-->ClO(X (II)-I-2) + O(S-1) and OClO + hv --> ClO(A (II)-I-2) + O(P-3) channels might also exist in addition to the ClO(X (II)-I-2) + O((3)(P) over bar, D-1) channel. Sn the triple diss ociation process, experimental results show that the main product chan nel is the OClO+hv-->Cl(P-2)+O(D-1)+O(P-3) channel, while the OClO+hv- ->Cl(P-2)+O(P-3)S. 0(3P)+0(P-3) channel is the minor one. The; branchi ng-ratio of these two channels is determined to be 0.89:0.11. From the modeling of the time of flight spectra of the O atom product, it is; believed:that the triple dissociation process of OClO is a simultaneou s process within the time scale of one rotation period. Two-photon dis sociative ionization process OClO+hv-->Cl++O-2+e(-) has also been obse rved. (C) 1998 American Institute of Physics.