Abstract: The vibrational energy transfer of I2 in argon solution confined in a nano-spherical cavity has been simulated by the equilibriummolecular dynamics (EMD) approach. The solute vibrational energy relaxation time T1, as a function of the radius of the spherical cavity and the solvent density, is calculated and discussed. According to the analysis of intermolecular interactions at atomic and molecular level, the reason of T1 increasing with the cavity radius decreasing is explored. The results showed that the geometry confinement and surface effect played an important role in the solvent distribution, which would influence the vibrational relaxation significantly. In addition, the simulations of bulk system indicated the values of T1 obtained by EMD and non-equilibrium molecular dynamics (NEMD)
were in good agreement for I2/Ar system.

Key words: Nano-confined solution, Equilibriummolecular dynamics, Vibrational energy relaxation time, Radial density distribution, Non-equilibriummolecular dynamics