FEMTOSECOND STUDIES OF CHARGE SEPARATION IN PHOTO-EXCITED DCM IN LIQUID SOLUTION

The solvatochromism of DCM in the fluorescent state has been studied using the femtosecond fluorescent up-conversion technique with a time-resolution of almost-equal-to 150 fs. It is shown that intramolecular charge separation is not complete within 300 fs after the excitation pulse. A significant portion of the charge separation trajectory ( almost-equal-to 30%) is controlled by the solvation process on a picosecond time scale. It is inferred that in photo-excited DCM the locally excited and charge transfer states mix in the strong adiabatic coupling limit in the inverted region.