INFLUENCE OF THE RADIATION-FIELD ONTO THE PHOTODISSOCIATION

The influence of the photoabsorption process on the photodissociation is investigated. To this end, the photodissociation of HCl as a model system is studied, by integrating numerically the time dependent Schro dinger equation for the simplified two-electronic-state problem, with the time dependent coupling between the two states via the electromagn etic radiation field included explicitly. The limits of the approximat ion, which does not consider the absorption process explicitly, is dis cussed. In this approximation the initial wave packet in the upper sta te is obtained by projecting the vibrational function of the electroni c ground state with the electronic transition dipole onto the upper el ectronic state. Thus the absorption process is considered only implici tly. It is demonstrated that the profile of the laser pulse and the he ld strength of the light has a decisive influence on the dissociation rates and the product distributions of the fragments. This cannot be d escribed by using the approximation discussed.