Concerning the existence of H− ion in irradiated solvent matrices at 77 K studied by stimulated luminescence

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Abstract
The attribution of the ∼1050 nm stimulation luminescence (SL) band in γ‐irradiated pure solvent matrices at 77 K to the anion H− is further supported by the present SL results observed on irradiated neutral or acidic solid solutions of tetramethyl‐p‐phenylenediamine (TMPD), tryptophan, or diphenyl‐p‐phenylenediamine (DPPD) in methylcyclohexane (MCH), 4.5M CaCl2ices and 2‐methyltetrahydrofuran (MTHF). Depending on the location of its SL band, at the red side or the blue side of the e − s one, the anion H− can decay faster or slower, respectively, relative to the e − s in the irradiated matrix. The present two photon bleaching SL experiments in the region below the SL energy threshold support the suggestion that the e − s optical absorption band in γ‐irradiated MTHF consists of many underlying discrete bands. There are three strongly overlapping bands : 1050, 1200, and 1400 nm. One of these, the 1050 nm, would be related to the anion H−. The effect of the γ‐dose rate on the SL intensity in irradiated TMPD–MCH and DPPD–MTHF glasses at 77 K reveals that (a) for the same total γ‐dose the formation of solvent radical is more pronounced in samples with higher γ‐dose rate; (b) the solvent radical anion(s) might have an optical absorption band located in the same region as the e − s one.