Photoelectron Emission Spectroscopy of Solvated Electron Solutions

Abstract

Instrumentation and methodology were developed for photoelectron emission (PEE) spectroscopy of sodium solutions in hexamethyl phosphoric triamide (HMPA) for irradiation from 1 to 3.7 eV. PEE currents were corrected by the Thomson equation for back scattering in the gas (nitrogen at 200–800 torr) above the solution. The Schottky effect for PEE was smaller than for thermionic emission and decreased with increasing photon energy. PEE spectra exhibited two steps corresponding, respectively, to emission by solvated electron species and metal species. The corresponding thresholds, obtained from Einstein plots, are approximately 1.4 and 2.6 eV. The first threshold is compared with the energy of the 1s state for a simple cavity model. Quantum yields were low, e.g., 10⁻⁵ emitted electron per incident photon. Thermionic and PEE currents are correlated.