中文摘要：

氧硫化碳（OCS ）在吸收230 nm左右的光子后迅速解离，生成的CO （X1Σ＋g ，v＝0，J＝42～65）碎片通过（2＋1）共振增强多光子电离后检测．通过对CO＋进行速度成像，获得了CO＋的平动能布居和角度分布．除了主要的单重态通道S（1D）＋CO（X1Σ＋g ，v＝0）以外，三重态解离通道形成的S（3 P）原子也被观测到，其通道分支比约为0.5％，并且随CO的转动激发而略增加．结合最新计算的OCS电子激发态势能面，获得了OCS的三重态解离机理：OCS吸收230 nm光子被激发至A 1 A′态，进而通过旋轨耦合至b3 A″态解离．

英文摘要：

Carbonyl sulfide （OCS） was excited and dissociated at ~230 nm ,and the CO（X1Σ＋g ,v=0 ,J=42~65） fragment was detected by using （2＋1） resonance‐enhanced multiphoton ionization at 229.825-230.000 nm .From the velocity map image of CO ＋ ,the kinetic energy and angular distributions of CO fragments were directly obtained .Besides the dominated channel of S （1 D）＋CO（X1Σ＋g ,v=0） ,S（3 P） atom was also observed in photodissociation of OCS at 230 nm .The branching ratio of the S （3 P） channel was about 0.5% ,and slightly increased with the rotational excitation of CO fragment from J=56 to 65 .With the aid of the recent high‐level potential energy surfaces of the excited electronic states of OCS ,the S（3 P） formation mechanism was proposed .Once absorbing an ultraviolet photon at ~230 nm ,the excited OCS in A1 A′state is produced initially ,and then dissociates to yield S （3 P） atom via spin‐orbital coupling to b3 A″state .