MOLECULAR-DYNAMICS SIMULATION OF SPECTRAL AND DYNAMIC SOLVENT EFFECTS FOR ELECTRONIC-TRANSITIONS OF NAI IN AR

To study the time dependence and the magnitude of solvent effects due to solvent electronic polarizability (in contrast to those due to reorientation of polar solvent molecules), we use molecular dynamics to calculate the electronic spectra and solvent relaxation for the transitions between the ionic ground state and a covalent excited state for a model of NaI in argon solution. We find large shifts of the spectra as a function of solvent density. The translational solvent relaxation around the solute in the new electronic state produces energy shifts of the order of a few kcal/mol and shows rapid change lasting approximately 200 fs followed by a longer tail. Such electronic polarizability solvent effects are expected to be universally present in transitions that change the solute charge distribution.