PHOTODISSOCIATION OF CS2 AT 193 NM INVESTIGATED BY POLARIZED PHOTOFRAGMENT TRANSLATIONAL SPECTROSCOPY

The predissociation dynamics of CS2 in the <(A)over tilde>(B-1(2)) sta te have been investigated by means of high resolution photofragment tr anslational spectroscopy at 193 nm. The photofragment translational en ergy distributions derived from the time-of-night (TOF) distributions of the CS fragment are qualitatively similar to the ones obtained in p revious investigations. Detailed measurements carried out with a linea rly polarised photolysis laser reveal a pronounced anisotropy of the f ragment recoil which is dependent on the translational energy and on t he molecular beam carrier gas. It is possible to partition each TOF di stribution of the CS fragment into two components corresponding to the formation of S(P-3) and S(D-1) partner fragments, respectively, in a manner consistent with recent branching ratio determinations. In the c ase of the Ne beam this partitioning leads to the anisotropy parameter s beta(S D-1)approximate to 0.2 and beta(S 3P)approximate to 1.0. Thes e results indicate that the overall photodissociation process occurs o n a time scale of similar to 1.5 ps and that the formation of CS + S(D -1) proceeds through a strongly bent transition state.