Photolysis of n-butyl nitrite and isoamyl nitrite at 355 nm: A time-resolved Fourier transform infrared emission spectroscopy and ab initio study

TL;DR

This study investigates the photodissociation of n-butyl nitrite and isoamyl nitrite at 355 nm using time-resolved IR emission spectroscopy and ab initio calculations, revealing similar NO fragment distributions and minimal effects of molecular substitution.

Contribution

It provides new insights into the similar photodissociation dynamics of two alkyl nitrites through combined experimental and theoretical approaches.

Findings

Similar rotational and vibrational NO distributions for both species

Close resemblance in IR emission temporal profiles

Minor effect of methyl substitution on dissociation dynamics

Abstract

We report on the photodissociation dynamics study of n-butyl nitrite (n-C_4H_9ONO) and isoamyl nitrite ((CH_3)_2C_3H_5ONO) by means of time-resolved Fourier transform infrared (TR-FTIR) emission spectroscopy. The obtained TR-FTIR emission spectra of the nascent NO fragments produced in the 355-nm laser photolysis of the two alkyl nitrite species showed an almost identical rotational temperature and vibrational distributions of NO. In addition, a close resemblance between the two species was also found in the measured temporal profiles of the IR emission of NO and the recorded UV absorption spectra. The experimental results are consistent with our ab initio calculations using the time-dependent density functional theory at the B3LYP/6-311G(d,p) level, which indicate that the substitution of one of the two {gamma}-H atoms in n-C_4H_9ONO with a methyl group to form (CH_3)_2C_3H_5ONO has only a minor effect on the photodissociation dynamics of the two molecules.