Effect of frequency-dependent friction for the excited-state isomerization dynamics of 2-vinylanthracene in solution

The effect of solvent friction on the excited-state isomerization rate of 2-vinylanthracene in solution is studied. Experimental results indicate a significantly small viscosity dependence in a series of compressed alkane solvents in the moderate-to-large viscosity region. This viscosity dependence is much smaller than that predicted by Kramers theory with zero-frequency friction. To understand this fact, the frequency-dependent friction Gz(λr) which has been defined by Grote-Hynes theory is calculated using the method of Bagchi and Oxtoby.