SOLVATION DYNAMICS IN MOLTEN-SALTS

We have observed time-dependent shifts in the fluorescence spectra of solvatochromic probe molecules in several molten tetraalkylammonium sa lts. The phenomenon is a general one and is observed in a variety of f luorophores. The steady-state emission position shows a pronounced dep endence on the molten salt cation size. Frequency shifts in steady-sta te emission spectra are a function of the solute. The solvation of exc ited large dipoles occurs on two time scales which are both dependent on the cation size. The larger the cation size, the longer the relaxat ion time. The average experimental solvation time, (T), for the same m olten salt depends on the solute. The observed results suggest that mo lten salts are an appropriate medium for studying excited large dipole solvation.