Abstract: | A close coupled treatment in a vibrational adiabatic representation is applied to the study of molecular photodissociation dynamics. The procedure which is developed here involves three steps: transformation from a diabatic to an adiabatic basis set, truncation of the adiabatic basis set, back transformation to a reduced–diabatic basis set. In the two model cases which are studied, dissociation spectra show complicated peaks and dips, patterns interpreted in terms of shape and Feshbach resonances associated to vibrational predissociation with a relatively high potential barrier in the excited state. An important reduction in the number of channels required for a given final accuracy can be reached by using the reduced–diabatic basis set instead of the usual diabatic one. This is very promising for studying energy partitioning in molecular systems with several internal degrees of freedom taking part in the dynamics. |