The extension of wave operator-Floquet formalism to molecular photodissociation processes with short laser pulses

Photodissociations induced by intense short laser pulses are investigated using a generalized Floquet formulation. This formulation replaces the continuous electric field shape function by a discrete step function. An initial active space is defined by using the Bloch’s wave operator theory and the corresponding target spaces, in which the dynamics is confined, are built for each new discrete value of the electric field magnitude. A powerful computational method of calculation of dissociation probabilities is elaborated on by calculating and storing some basic data at each step of the discretized shape function—the eigenvalues of the target spaces, the overlap matrix between two successive groups of Floquet eigenvectors, and finally the projection of the Floquet eigenvectors onto the bound states. The calculation is achieved by exploiting these data in a fast integration of the dynamic projected into the active space. An illustrative example, concerning the photodissociation of H+2, reveals that the procedure is particularly suitable for studying the influence of the pulse shape.