Vibrational energy relaxation of a diatomic molecule in a room-temperature ionic liquid

摘要: Vibrational energy relaxation (VER) dynamics of a diatomic solute in ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate (EMI(+)PF(6) (-)) are studied via equilibrium and nonequilibrium molecular simulations. The time scale for VER is found to decrease markedly with the increasing dipole moment, consonant many previous studies polar solvents. A detailed analysis results shows that dipolar solute, dissipation an excess vibrational occurs almost exclusively Lennard-Jones interactions between solvent, while oscillatory exchange two mainly controlled by their electrostatic interactions. Regardless anharmonicity potential, becomes accelerated as initial increases. This attributed primarily enhancement variations solvent force on bond, induced large-amplitude vibrations. One interesting finding if variable scaled excitation employed, tend show universal behavior irrespective its state. Comparison water acetonitrile overall characteristics EMI(+)PF(6) (-) similar those acetonitrile, much faster than two. It also Landau-Teller theory predictions obtained simulations autocorrelation function reasonable agreement results.