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

TL;DR

This study uses quantum mechanical calculations to analyze the kinetic energy release distributions in pyrrole photodissociation, providing detailed insights into the fragmentation process and matching experimental results.

Contribution

It introduces a novel ab initio quasi-diabatic potential energy matrix and an efficient adiabatic mapping approach for calculating TKER distributions in pyrrole photodissociation.

Findings

Calculated TKER distributions agree with experimental data.

Spectral peaks are assigned and interpreted in detail.

The approach enhances understanding of pyrrole's photodissociation dynamics.

Abstract

The analysis of the total kinetic energy release (TKER) of the photofragments pyrrolyl + H-atom formed in the photodissociation of pyrrole in the low-lying state $^1\!A_2(\pi \sigma^*)$ is presented. The TKER distributions contain complementary and often more precise information on the fragmentation process than the broad diffuse absorption spectra. The distributions are calculated quantum mechanically for the diabatic state $^1\!A_2(\pi \sigma^*)$ either isolated or coupled to the ground electronic state at an exit channel conical intersection. The calculations use the novel ab initio quasi-diabatic potential energy matrix constructed in paper I. The approximate overlap integral-based adiabatic mapping approach is introduced with which the quantum mechanical TKER distributions can be efficiently and accurately reproduced. Finally, the calculated TKERs are compared with the experimental results. The main features of the measured vibrationally resolved distributions are reproduced, and the spectral peaks are assigned and interpreted in detail.