Molecular Ions in Radiation Chemistry. III. Absorption Spectra of Aromatic-Hydrocarbon Cations and Anions in Organic Glasses

Aromatic hydrocarbons (ArH) in γ-irradiated, glassy butyl chloride at 77°K are efficient traps for migrating positive holes, forming the radical cations of 40 compounds in good yield. No ArH− ions appeared to form. Photobleaching is very inefficient, or nil. Resonance charge transfer and simple competition for holes by ArH, solvent, and anions are consistent with observation. In glassy methyltetrahydrofuran, ArH gave ArH− in good yields with very little ArH+. In 3-methylpentane, both ArH+ and ArH− were formed. Addition of propyl chloride enhanced ArH+ and suppressed ArH−. Addition of ethanol had the reverse effect.