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Keywords:

  • resonance Raman spectroscopy;
  • quantum chemical calculations;
  • proton transfer;
  • time-dependent analysis

Abstract

1-Hydroxy-2-acetonaphthone (HAN), an intramolecular proton transfer system, was investigated in the present study by means of quantum chemical calculations and resonance Raman spectroscopy. To determine the Franck–Condon parameters, a time-dependent approach for the analysis of the resonance Raman spectra was applied. About 18 vibrational modes were found to be involved in the initial dynamics of HAN upon photo excitation. Moreover, the excited-state geometry of HAN was optimized at the CASSCF level of theory and the displacement parameters were determined. A very good agreement between the theoretical and experimentally derived parameters was obtained. The vibrations with the highest displacements correspond to stretching and in-plane deformation modes of the naphthalene ring and the conjugated carbonyl group, while the OH stretching mode exhibits no observable enhancement. Hence, a general molecular rearrangement takes place upon photo excitation, where the intramolecular oxygen–oxygen distance reduces corresponding to a redistribution of the electron density. Copyright © 2006 John Wiley & Sons, Ltd.