Probing Local Environments by Time-Resolved Stimulated Emission Spectroscopy

Abstract

Time-resolved stimulated emission spectroscopy was employed to probe the local environment of DASPMI ( 4-(4-(dimethylamino)styryl)-N-methyl-pyridinium iodide ) in binary solvents of different viscosity and in a sol-gel matrix. DASPMI is one of the molecules of choice to probe local environments, and the dependence of its fluorescence emission decay on viscosity has been previously used for this purpose in biological samples, solid matrices as well as in solution. The results presented in this paper show that time-resolved stimulated emission of DASPMI is a suitable means to probe the viscosity of local environments. Having the advantage of a higher time resolution, stimulated emission can provide information that is complementary to that obtained from fluorescence decay measurements, making it feasible to probe systems with lower viscosity.