Photodissociation dynamics in the first absorption band of pyrrole: II. Photofragment distributions for the $^1\!A_2(\pi \sigma^*) \leftarrow ilde{X}^1\!A_1(\pi\pi)$ transition

摘要

The analysis of the total kinetic energy release (TKER) of the photofragmentspyrrolyl + H-atom formed in the photodissociation of pyrrole in the low-lyingstate $^1\!A_2(\pi \sigma^*)$ is presented. The TKER distributions containcomplementary and often more precise information on the fragmentation processthan the broad diffuse absorption spectra. The distributions are calculatedquantum mechanically for the diabatic state $^1\!A_2(\pi \sigma^*)$ eitherisolated or coupled to the ground electronic state at an exit channel conicalintersection. The calculations use the novel ab initio quasi-diabatic potentialenergy matrix constructed in paper I. The approximate overlap integral-basedadiabatic mapping approach is introduced with which the quantum mechanical TKERdistributions can be efficiently and accurately reproduced. Finally, thecalculated TKERs are compared with the experimental results. The main featuresof the measured vibrationally resolved distributions are reproduced, and thespectral peaks are assigned and interpreted in detail.