Temperature dependent vibrational lifetimes in supercritical fluids near the critical point

摘要: Vibrational relaxation measurements on the CO asymmetric stretching mode (similar to 1980 cm(-1)) of tungsten hexacarbonyl (W(CO)(6)) as a function temperature at constant density in several supercritical solvents vicinity critical point are presented. In ethane, density, there is region above (Tc) which lifetime increases with increasing temperature. When raised sufficiently T-c + 70 degrees C), decreases further increase A recent hydrodynamic/thermodynamic theory vibrational fluids reproduces this behavior semiquantitatively. The dependent data for fixed densities somewhat and below better agreement theory. fluoroform solvent also initially However, CO2 approximately linearly beginning almost immediately T-c. does not reproduce behavior. comparison between absolute lifetimes three trends made.