Poster 0157: A novel continuum model for the calculation of solute-solvent dispersion contribution to the electronic excitation energy in solution.

In a recent work [1], we have presented a method to estimate the dispersion interaction energy between two molecules based on the measure of the electronic field fluctuations by means of quantum Monte Carlo (QMC) methodologies. The approach has been extended to the calculation of the dispersion contribution to the free energy of solvation within a continuum model framework. An explicit expression has been given and test calculations have been performed on atomic solutes in water as solvent. Here, we show for the first time, the generalization of the method to non-spherical solutes in ground an low lying excited states and in various solvents. The method involves the accurate calculation of the electronic wave function of the solute in ground and excited states while the solvent is treated as a continuum and is characterized by the refractive index and the ionization potential. We present results for different cavities. In all our calculations, we observe a red shift due to this contribution in the vertical electronic excitation energy of the solute. [1] C. Amovilli and F. M. Floris, J. Phys. Chem. A 119: 5327 (2015