Abstract:

The radial distributions of argon as a solvent as well as the vibrational relaxation dynamics of the solute I2 confined in a single-walled carbon nanotube (SWCT) were investigated by mixed quantum-classical molecular dynamics simulations. Functions of the vibrational frequency shift and the vibrational relaxation time of I2 with varying radii were presented. Using the frequency shift of I2 as a spectral probe, an analysis of the instantaneous interactions of I2 with the surroundings was determined by breaking down the shift into the contributions of the nanotube and the solvent atoms. Detailed mechanistic information related to the shift was investigated at the atomic and molecular level. In addition, by analysis of the sensitivity of the spectral probe and the dependence of the frequency shift on the vibrational relaxation time of the probe molecule, we conclude that the frequency shift is a good spectral probe to investigate the interactions in confined condensed phases.

Key words: Vibrational spectral probe, Mixed quantum-classical molecular dynamics, Single-walled carbon nanotube, Vibrational relaxation time, Vibrational frequency shift