Dynamics of H atom production from photodissociation of H2O2 at 205 nm

Photodissociation dynamics of H2O2 at 205 nm producing H atoms has been investigated by measuring laser-induced fluorescence spectra of H. From Doppler profile analyses, the average translational energy release was found to be 150.4 ± 70.1 kJ/mol with the anisotropy parameter, −0.35 ± 0.05 for the characteristic perpendicular transition. Potential energy surfaces for the S0, S1, and T1 electronic states along the dissociation coordinates were obtained employing density functional theory calculations at the B3LYP/aug-cc-pVTZ level. The dissociation of H from H2O2 instantaneously takes place along the repulsive part of the triplet surface via rapid intersystem crossing from the initially excited S1 state.