Alternative Mechanisms for Solvation Dynamics of Laser-Induced Electrons in Methanol

Abstract

A multiphoton ionization study of neat methanol with subpicosecond 2-eV laser pulses has been previously reported. A hybrid electron solvation mechanism combining both a stepwise transition between two electronsolvent configuration states and a continuous first-order blue shift of the electron absorption spectra was found to closely fit the experimental data. If substantial absorption from free electrons is assumed in this spectral region, we find that another model comprising thermalization prior to a stepwise branching localization without blue-shifting spectra fits equally well at all wavelengths. However, these two models display considerable differences between their respective kinetic parameters, especially the electron localization time. Furthermore, for the nonshifting model, this calculated localization time is considerably longer than that for electron hydration in neat water. We suggest independent studies such as ultrafast electron scavenging experiments before adopting a particular mechanism for electron solvation in methanol.