Abstract

The investigations of fast molecular processes, in which porphyrins complexes with transition metals are involved, is of great importance for elucidating the energy and charge transfer processes in native biological systems. The Ni(II)- and Cu(II)-porphyrins (P) are the promising model compounds to be investigated because of the rich variety of physical- chemical phenomena they demonstrate. To extract information on dynamic behaviour of the molecule usually laser pulses are used having duration comparable or shorter than the excited states lifetimes [1-4]. In the present research we have adopted another approach to obtain transient Raman spectra under deep radiative saturation of one-photon transitions involved. The investigated Me-P have typical decay times in subnanosecond time domain. So, it is possible to produce a quasi-stationary distribution of the molecules over electronic energy levels tracing the temporal profile of the nanosecond laser pulse. As a result Raman spectra from the ground and/or excited states can be recorded and the population redistribution over the excited states can be examined as a function of excitation power.

© 1992 Optical Society of America