Effects of solute electronic polarizability on solvation in a room-temperature ionic liquid.

The effects of solute polarizability on solvation and solute transport in the room-temperature ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate (EMI+PF(6)-) are investigated via molecular dynamics simulations. A valence-bond description is employed to account for the instantaneous adjustment of the solute electronic charge distribution to the fluctuating solvent environment. It is found that the ultrafast inertial component of solvation dynamics becomes slower as the solute polarizability grows. Moreover, its contribution to overall solvent relaxation becomes reduced with increasing polarizability, especially in the case of nonequilibrium solvation dynamics. Overall, the inclusion of the solute electronic polarizability in the simulations improves the agreement with time-dependent Stokes shift measurements.