Effect of molecular bending on the photodissociation of OCS (original) (raw)

At 230 nm, the photodissociation of OCS via a hot band and a triplet state was investigated by selective probing of high rotational levels of product CO (Jϭ45-67) with photofragment imaging spectroscopy: OCS(vϭ0)ϩh(UV͒→CO(X 1 ⌺ ϩ ,Jу65)ϩS(3 P), OCS(vϭ1)ϩh(UV͒ →CO(X 1 ⌺ ϩ ,Jϳ65)ϩS(1 D). Additional two-photon IR excitation of the UV photoprepared OCS with intense 1.06 m laser pulses bleaches the UV processes listed above and induces a new excitation channel of OCS: OCS(vϭ0)ϩh(UV͒→OCS*, OCS*ϩ2h(IR͒→CO(X 1 ⌺ ϩ ,J ϳ74)ϩS(1 S). The bending mode of OCS in the excited states plays a central role in the excitation and dissociation dynamics. Additionally, the alignment effect of OCS by nonresonant infrared laser pulse, which appears on the angular distribution of the photofragment, is discussed.