Molecular dynamics simulations on vibrational energy transfer and diffusion of I2/Ar solution confined in a cylindrical nanotube have been performed. The solute vibrational energy relaxation time T1, as well as the solvent diffusion coefficient Dz along the nanotube was calculated as a function of radius of the nanotube. The results show that the T1 decreases as the radius increases, while the Dz takes the opposite trend. The confinement effect of the nanotube weakens quickly as the radius becomes larger, and as a result, both T1 and Dz tend towards the values of a bulk system as we expected. In addition, the mechanism of confinement effect on energy transfer and mass transport was explored at an atomic/molecular level by investigating the interactions among the nanotube, solute iodine and solvent argon.

Key words: molecular dynamics simulation, radial density profile, vibrational energy relaxation time, diffusion coefficient, cylindrical nanotube