225∽260 nm波段溴化氰光解动力学系统性研究

本文报道了在自行搭建的时间切片离子速度成像装置上进行的225∽260 nm波段内溴化氰光解动力学的研究. 在该波段内选取了若干溴原子(²P_3/2或²P_1/2)的共振线对产物溴原子的共振电离并采集其切片影像，得到了光解产物的总平动能谱，进而获得了产物氰基的振转态布居等信息. 本文发现了在Br^*通道，产物氰基的内能激发比Br通道低；Br和Br^*通道产物氰基振动的最高布居分别为v=0和1. 另外，还发现对于Br通道，溴化氰分子在长波处与短波处解离时，氰基产物的振转激发差异很大，这揭示了其显著不同的光解动力学.

Systematical Study on Photodissociation Dynamics of BrCN from 225 nm to 260 nm

The photodissociation dynamics of Br-C bond cleavage for BrCN in the wavelength region from 225 nm to 260 nm has been studied by our homebuilt time-slice velocity-map imaging setup. The images for both of the ground state Br(²P_3/2) and spin-orbit excited Br^?(²P_1/2) chan-nels are obtained at several photodissociation wavelengths. From the analysis of the trans-lational energy release spectra, the detailed vibrational and rotational distributions of CN products have been measured for both of the Br and Br^? channels. It is found that the internal excitation of the CN products for the Br^? channel is colder than that for the Br channel. The most populated vibrational levels of the CN products are v=0 and 1 for the Br and Br^? channels, respectively. For the Br channel, the photodissociation dynamics at longer wavelengths are found to be di erent from those at shorter wavelengths, as revealed by their dramatically different vibrational and rotational excitations of the CN products.