PUMP-PROBE STUDIES OF THE EFFECTS OF PERMANENT DIPOLES IN ONE-COLOR AND 2-COLOR MOLECULAR EXCITATIONS

The effects of a non-zero difference, d, between the permanent dipole moments, mu(jj), of two electronic molecular states involved in a sing le-or multi-photon transition, on the temporal evolution and the spect ral behaviour of the states can be substantial. New results for the el ectronic energies and the transition and permanent dipole moments for a series of substituted diphenyl giant dipole molecules are used to ex tend previous investigations, which involved two- or very few-level mo del systems, to many-level systems, interacting with one or two contin uous wave lasers. Both exact Floquet calculations and the rotating wav e approximation are used in this study. Emphasis is placed on the effe cts of permanent dipoles, and of other molecular states, on single- ve rsus multi-photon, and one- versus two-colour, transitions between two states embedded in many-level (up to eight) manifolds of states. One- colour, one- and two-photon, and two-colour, (0, 1 ) - and ( 1, 1) -ph oton, transitions are investigated explicitly and particular attention is placed on the temporal evolution of the relevant molecular states. Analytic two-level rotating wave expressions for the one- and two-col our molecule-laser(s) coupling are particularly useful in helping to i nterpret and/or predict the effects of permanent dipoles and neighbour ing states on the transition of interest.