Reorientatlon and Isomerization of trans-Stllbene in Alkane Solutions

Rotational reorientation times were obtained for trans-stilbene in the series of n-alkanes over a wide temperature range by using picosecond anisotropic absorption measurements and fluorescence depolarization measurements. The data show that the coupling of solute and solvent decreases as the size of the solvent increases. However, in a given solvent the reorientation depends linearly on a / T over our temperature range. The results are discussed in the context of the free space model of Dote et al. The new data are used to discuss the applicability of current models for activated barrier crossing to the isomerization of stilbene.