Photodissociation of H2O2/D2O2 from the Lowest Excited State: The Origin of Fragment Rotation

In order to elucidate the photofragmentation dynamics of small non‐planar molecules, hydrogen peroxide was prepared in its first excited electronic state, Ã1A. The variety of scalar (internal state distribution, translational energy) and vectorial (angular distribution, rotational alignment, correlations between rotational and translational motion) properties of the resulting hydroxyl radicals was analysed by LIF‐Doppler and ‐polarisation spectroscopy. The influence of the upper state repulsive potential and of initial parent vibrational excitation on final product rotation was determined by using deuterium peroxide and internally cold parent molecules.