Femtosecond relaxation dynamics of solvated electrons from liquid metal-ammonia solutions: Temperature jump versus local density jump

Abstract

Localization phenomena of excess electrons in condensed phases have been the subject of extensive femtosecond (fs) time-resolved experiments in the past. The primary focus was on elucidating the relaxation dynamics of solvated electrons in liquid water where their preparation can be accomplished by laser-induced detachment either from the solvent or from suitable solutes. This chapter presents two distinct non-adiabatic relaxation scenarios for interpreting the fs-spectral response of solvated electrons from metal–ammonia solutions—namely, the local temperature-jump and the local pressure-jump models. Both models rely on a minimum number of free adjustable parameters to simulate the experimental transients and require no input other than the shape of thermalized linear electronic resonance of the solvated electron and its dependence on the thermodynamic state variables of the fluid. Depending upon what model is preferred, the time-dependent solvated electron resonance merely serves as a local thermometer or a local densitometer of its own solvent cavity following the ultrafast non-adiabatic transition.