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

In this paper we present two computational strategies to simulate resonance Raman spectra of sol- vated 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 dynam- ics. 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 poten- tial energy surface. In both strategies we have applied the recent advances achieved in the QM description of excited state properties and geometries of solvated mol- ecules. In particular, linear response approaches such as CIS and TDDFT, and their extensions to analyt- ical gradients, are here used to evaluate the quanti- ties 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 experi- mental RR spectra seems to confirm the reliability of the computational strategies based on the PCM description.