Ab initio study of the photodissociation of nitrosoalkanes and nitrosamines

The primary step of the photodissociation in CH3N0 and NH2NO has been investigated by ab initio SCF-CI techniques. first singlet excited state presents a barrier along the dissociation coordinate both for CH3N0 and for the planar form NH2N0. However, NH2N0 prefers a twisted and pyramidalized structure in SI, with no barrier to dissociation. These of the SI surface explain the observation of a vibrational structure in the n - T* spectrum of (CH3)2NN0, dominate dissociation mechanism (vibrational predissociation vs. intersystem crossing or internal conversion), and may influence quantum yields in the condensed phase.