The effect of excited state absorption of dimeric chlorophyll on the Raman spectrum of the solvent

Abstract

Pulsed laser-induced Raman spectra of dimeric chlorophyll u in the solvent hexane are reported where the wavelength of the exciting radiation is in resonance with the position of the Soret band of the solute. As a result of the Occurrence of effective population saturation of nanosecond-and picosecond-lived S, and S, excited states of the dimer, changes take place in the absorption spectrum of the irradiated part of the solution from which Raman emission of the solvent occurs. The intensity of the observed Raman bands of hexane of different shifts are influenced in a different way by the change in the transmission of the medium. A correlation is made of these changes and the said Raman intensities.

Relative cross section and time-resolved fluorescence of porphyrin–DNA complexes

“…Also, the excited state absorption spectrum of porphyrin molecules may replace in part that of the ground state and the intensity of the Raman band of water could change as a result of absorption of the Raman emitted light by the excited state of porphyrin molecule (15). The observed behaviour of the value of the cross section for ZnTMpyP and H2TMpyP-DNA complexes with r >_ 800 is thought to be mainly caused by the onset of stimulated emission.…”