Photodissociation Dynamics of OCS near 150 nm: The S(1S J=0) and S(3PJ=2,1,0) Product Channels.
Photodissociation Dynamics of OCS near 150 nm: The S(1S J=0) and S(3PJ=2,1,0) Product Channels.
复制标题
DOI：
10.1021/acs.jpca.0c03823
复制
发表时间：
2020-07
期刊：
影响因子：
--
通讯作者：
Ting-xian Xie;Wentao Chen;Daofu Yuan;Shengrui Yu;Bina Fu;Kaijun Yuan;Xueming Yang;Xingan Wang
中科院分区：
文献类型：
--
作者：
Ting-xian Xie;Wentao Chen;Daofu Yuan;Shengrui Yu;Bina Fu;Kaijun Yuan;Xueming Yang;Xingan Wang
利用时间切片速度图离子成像技术研究了羰基硫（OCS）的真空紫外光解离动力学。在147.24 ~ 156.48 nm的6个波长下，获得了OCS光解生成的S（1 SJ =0）和S（3 PJ = 2，1，0）光碎片的图像。CO副产物的振动态在图像中被部分解析和识别。观察到两个主要的解离产物通道：自旋允许的S（1 SJ = 0）+ CO（X1 μ g+）和自旋禁止的S（3 PJ = 2，1，0）+ CO（X1 μ g+）。在每个波长下，总的动能释放（TKERs），不同的CO振动态的相对布居和各向异性参数的推导。在S（3 PJ）沟道的不同自旋轨道态之间观察到相对布居数的变化。发现S（1 SJ =0）+ CO（X1 <$g+）通道主要由OCS的1 <$+<$1 <$+平行跃迁控制。有趣的是，在不同的光解波长下，自旋禁戒的S（3 PJ = 2，1，0）+ CO（X1 ~（？）g+）产物通道存在两种各向异性参数.在147.24和150.70 nm处的各向异性参数明显小于其他四个光解波长。这一现象表明，两种不同的非绝热路径是负责自旋禁戒通道，这是一致的势垒结构中的一个三重态的出口通道。
Vacuum ultraviolet (VUV) photodissociation dynamics of carbonyl sulfide (OCS) has been investigated by using the time-sliced velocity map ion imaging technique. Images of the S(1S J =0) and S(3PJ=2,1,0) photofragments formed in the OCS photodissociation were acquired at six photolysis wavelengths from 147.24 nm to 156.48 nm. Vibrational states of the CO co-products were partially resolved and identified in the images. Two main dissociation product channels: the spin allowed S(1SJ = 0) + CO(X1Σg+) and spin-forbidden S(3PJ=2,1,0) + CO(X1Σg+) were observed. At each photolysis wavelength, the total kinetic energy releases (TKERs), the relative population of different CO vibrational states and the anisotropic parameters were derived. Variations of the relative population were noticed between different spin-orbit states of the S(3PJ) channel. It was found that the S(1SJ=0)+ CO(X1Σg+) channel is dominated by the 1Σ+←1Σ+ parallel transition of OCS. Interestingly, two types of anisotropic parameters are found at different photolysis wavelengths for the spin-forbidden S(3PJ=2,1,0) + CO(X1Σg+) products channels. The anisotropic parameters at 147.24 and 150.70 nm are significantly smaller than at other four photolysis wavelengths. This phenomenon indicates two different nonadiabatic pathways are responsible for the spin-forbidden channels which is consistent with the barrier structure in the exit channel of one of the triplet states.