Spectra of electrons trapped in ethylene glycol-hexamethylphosphoric triamide glasses

Abstract

Spectra of electrons in ethylene glycol (EG)-hexamethylphosphoric triamide (HMPA) were studied at 77 K and higher temperatures as a function of matrix composition. The changes of such spectral characteristics as position of maximum, half-width of electron band and the yield of trapped electrons were interpreted in terms of a simple two-site model of electron trapping. Shallow trapped electrons are located among HMPA molecules while deeply trapped electrons are located inside EG clusters. The process of EG clustering starts stepwise at ∼50 mol% EG. The interpretation of spectral changes at higher temperatures is more complex because of the different thermal stability of electrons located in traps of various depths.