中文摘要：

用时间切片速度成像方法研究了氦液滴中羰基硫（COS）分子的光解动力学. 从共振增强（2＋1）电离的CO光谱中发现在氦液滴环境中解离产物CO的转动冷却比振动冷却更有效.利用速度成像采集到的CO （v=0）和CO （v=1）的影像在角分布上都呈现出各向同性的特点. 产物平动能分布的结果表明尽管大部分的平动能都被超流体环境所弛豫, 但振动激发态产物CO （v=1） 的平均平动能比振动基态产物CO （v=0） 的平均平动能高.对羰基硫分子在氦液滴中的光解动力学机理进行了讨论.

英文摘要：

The photodissociation dynamics of carbonyl sulfide （OCS） in helium droplets was studied using a velocity-map-imaging technique. The CO fragments were detected by （2 ＋ 1）-resonance-enhanced multiphoton ionization. It was found that in the helium droplet environment, rotational cooling is much more efficient than vibrational cooling. The velocity map images for both CO （v=0） and CO （v=l） exhibit nearly isotropic angular distributions. The kinetic energy distributions show that most of the translational energies are relaxed in the finite-sized superfluid helium system. However, the average translational energies of the CO （v=l） images are higher than those of the CO （v=0） images. The relevant mechanism is briefly discussed.