Photodissociation dynamics using degenerate four-wave mixing spectroscopy

Abstract

Peroxides play a very important role in the combustion process and in atmospheric chemistry. In this experiment, the photodissociation dynamics of tert-butyl hydroperoxide at 213 nm and at room temperature was compared with that of hydrogen peroxide. This gives an information on the effect of the substitution of H with t-Bu group, hence a detailed picture on the photodissociation dynamics of peroxides. Photodissociation of Hydrogen Peroxide at 213 nm : Degenerate four-wave mixing (DFWM) spectroscopy has been used to investigate the nascent hydroxyl (OH) radical from the photolysis of hydrogen peroxide at 213 nm. In this experiment, rotational energy of OH has been found to be 2910 $cm^{-1}$ (9.7 % of the available energy) with a distribution peaking near at N`` = 7. The ∧-doublet ratio increasing with N was observed. No preference for one of the spin-orbit states was observed. The internal motion of product OH radical has been found to be vibrationally cold. Photodissociation of tert-Butyl Hydroperoxide at 213 nm : The photodissociation of tert-butyl hydroperoxide (t-BuOOH) at 213 nm has been studied. The nascent OH radical was observed using DFWM spectroscopy. The rotational energy was estimated to be 2880 $cm^{-1}$ (8.4% of the available energy), and the rotational distribution peaks near at N`` = 7. A propensity for $\pi^+$ ∧-doublet state was observed, and two spin-orbit states have been found to be statistically populated. No vibrationally excited OH has been found.