Mode specificity of vibrational energy relaxation of azulene in CO2 at low and high density

Results of the normal mode analysis of classical molecular dynamics simulations of azulene vibrational energy relaxation in carbon dioxide are presented for the first time. There is strong evidence for different energy transfer mechanisms dominating at low and high densities. At low pressure only the low-frequency vibrational modes of the solute participate in the energy transfer to the solvent whereas at high pressure almost all the vibrational modes contribute to the solute-to-solvent energy flow. The relevance of these results for experimental studies is discussed.