Trapped Electrons in Disordered Matrices

Abstract

Electrons generated by ionizing radiation or photoionization can be trapped in a variety of solids. Extensive studies have been carried out on trapped electrons in alkali halide crystals in which the electron is trapped in an anion vacancy in the crystal lattice [1]. These trapped electrons have an intense optical absorption in the visible and are thus called color centers or farben centers (F-center). Electrons may also be trapped in molecular crystals such as crystalline ice and a variety of polyhydroxy compounds such as alcohols and carbohydrates [2]. Electron trapping in molecular crystals containing hydroxy groups is qualitatively different than in alkali halides since facile rearrangements of hydrogen positions in the presence of an electron can occur in such molecular crystals. Thus, although there may be some vacancies or sites in molecular crystals with hydroxy groups oriented to favor trapping of an electron, the detailed geometry of the trapping site can be changed by the presence of the electron. This is analogous to the solvation of an electron in which the surrounding molecular groups are reoriented by the presence of the electron compared to their orientation in the absence of the electron.KeywordsElectron Spin ResonanceElectron Spin Resonance SpectrumOptical Absorption SpectrumTrap ElectronSolvation ShellThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.