Molecular dynamics modeling of time-resolved fluorescence shifts in liquid solution

Abstract

This paper presents equilibrium and nonequilibrium molecular dynamics simulation of the time‐dependent solvation shift of the fluorescence of 7‐amino 3‐methyl 1,4 benzoxazine 2‐one in methanol between 200 and 300 K. The linear response theory of solvation is found to work well for this system, even long after the inertial response. The development of the solvation shift is remarkably well correlated with the rotational dynamics of the pure solvent, by an empirical relation due to Maroncelli, Kumar, and Papazyan [J. Phys. Chem. 97, 13 (1993)]. The solute–solvent radial distribution functions show evidence of hydrogen bonding of the solvent to the solute in its excited state. The roles of some factors commonly neglected in simulation of solvation are discussed, e.g., the influence of internal degrees of freedom of the solute.