FRAGMENTATION DYNAMICS OF THE PHOTO-DISSOCIATED TRIATOMIC MOLECULE

A theory is presented of the angular momentum distribution of diatomic fragments ejected in the photodissociation of triatomic molecules. Th e theory is based on semi-classical dynamics and treats dissociation f rom an ensemble of nuclear configurations reflecting the zero-point os cillations of the parent molecule. The mean angular momentum of the di atomic is determined by the range parameter of the repulsive potential , while the width of its distribution is determined by the gradient pa rameters of the potential surface as expressed in the Franck-Condon sp atial and angular coordinates. The odd moments of the asymmetrical dis tribution are related to the nonlinear part of the potential energy su rface. Using available experimental data, the model is applied to the photodissociation of NOCl at 440 nm, leading to an estimated value of 0.2 eV rad-1 for the local angular gradient of the repulsive potential , and a consequent lower limit of 20 fs for the fragmentation time.