Resonance Raman spectra including absolute Raman cross section measurements
were acquired with excitation wavelengths within the MLCT absorption band
of [Pt(PEt3)(2)(C= CH)(2)]. The absorption and resonance Raman cross sectio
ns were simultaneously modeled with time-dependent wave packet calculations
to give an estimate of the vibrational reorganizational energies and initi
al structural changes of the excited state. We compare our results for [Pt(
PEt3)(2)(C=CH)(2)], which contains no phenyl groups, with previous results
for [Pt(dppm)(2)(PhC=C)(2)], which contains a number of phenyl groups. The
predominant nominal C=C stretch reaction coordinate and the vibrational reo
rganizational energies are significantly altered in the initial excited sta
te by the absence or presence of the aromatic substituents, and we semiquan
titatively estimate these changes.