TRANSIENT HOLE-BURNING OF S-TETRAZINE IN PROPYLENE CARBONATE - A COMPARISON OF MECHANICAL AND DIELECTRIC THEORIES OF SOLVATION

The solvation dynamics of s-tetrazine, a nonpolar solute, in propylene carbonate, a polar solvent, have been measured in the temperature range of 190-300 K and the time range of 1.5-300 ps by transient hole burning. A detailed model of the gas-phase spectrum of s-tetrazine is used to extract purely solvent-induced effects from steady-state and ultrafast spectra. Absolute measurements of the solvation response function are extracted from these spectra and are compared to dielectric and mechanical theories of solvation. Although the theories postulate very different solute-solvent interactions mechanisms, either theory can account for the available data. (C) 1995 American Institute of Physics.