A quantum mechanical polarizable continuum model for the calculation of resonance Raman spectra in condensed phase

Abstract

In this paper we present two computational strategies to simulate resonance Raman spectra of solvated molecules within the framework of the polarizable continuum model (PCM). These two strategies refer to two different theoretical approaches to the RR spectra, namely the transform theory and the short-time dynamics. The first is based on the explicit detemination of the mimimum geometries of ground and electronically excited states, whereas the second only needs to know the Franck–Condon region of the excited state potential energy surface. In both strategies we have applied the recent advances achieved in the QM description of excited state properties and geometries of solvated molecules. In particular, linear response approaches such as CIS and TDDFT, and their extensions to analytical gradients, are here used to evaluate the quantities required to simulate resonance Raman spectra. The methods have been applied to the study of solvent effects on RRS of julolidine malononitrile (JM). The good agreement found between the calculated and experimental RR spectra seems to confirm the reliability of the computational strategies based on the PCM description.