Rapid solvation of a nonpolar solute measured by ultrafast transient holeburning

Abstract

Holeburning spectra from 1 ps to 1.2 ns have been measured for dimethyl- s-tetrazine dissolved in glycerol triacetate. Clean excitation of the well-separated 0–0 vibronic transition insures that only solvent dynamics contribute to the hole broadening. The majority of the interaction relaxes in less than a picosecond, with a second process relaxing in ≈ 2 ps. This solvation process is much faster than the 700 ps dielectric solvation of a highly polar solute in the same solvent, as measured by time-resolved Stokes shifts.