OCS分子在128 nm附近的光解动力学研究:S(3PJ=2,1,0)、S(1D2)以及S(1S0)产物通道

Photodissociation Dynamics of OCS Near 128 nm:S(3PJ=2,1,0),S(1D2)and S(1S0)Channels

本文利用时间切片离子成像技术对OCS分子进行了真空紫外波段的光解动力学研究.在四个光解光波长(从129.32到126.08 nm)下测量了硫原子解离产物S(^3PJ=2,1,0)、S(^1D2)、S(^1S0)的速度影像,并从中清晰地发现了四个主要的解离产物通道:S(^3PJ=2,1,0)+CO(X^1Σ^+),S(^3PJ=2,1,0)+CO(A^3Π),S(^1D2)+CO(X^1Σ^+)和S(^1S0)+CO(X^1Σ^+).在实验影像中,产物CO分子的部分振动态结构能够得到分辨.实验还获取解离产物总平动能谱,产物分支比和角分布.对实验结果进行分析显示除绝热解离通道S(^3PJ=2,1,0)+CO(A^3Π)之外,在其他三个产物通道中非绝热效应都起到非常重要的作用.

Here we report the study of the photodissociation dynamics of carbonyl sulfide in the vacuum ultraviolet region using the time-sliced velocity map ion imaging technique.Images of S(^3PJ=2,1,0),S(^1D2)and S(^1S0)products were measured at four photolysis wave-lengths of 129.32,128.14,126.99,and 126.08 nm,respectively.Four main dissociation channels:S(^3PJ=2,1,0)+CO(X^1Σ^+),S(^3PJ=2,1,0)+CO(A^3π),S(^1D2)+CO(X^1Σ^+)and S(^1S0)+CO(X^1Σ^+)channels,have been clearly observed and identified.Vibrational states of the CO co-products were partially resolved in the experimental images.From these images,the product total kinetic energy releases,the branching ratios and angular distributions of products have been derived.While the S(^3PJ=2,1,0)+CO(A^3π)product channel is formed through the adiabatic dissociation process after the excitation to the(3^1Σ^+)excited state,the results suggest that strong nonadiabatic coupling plays an important role in the formation of other three channels.