ESR investigation of hydrogen atoms stabilized in γ-irradiated alkaline earth hydroxides

The results of an electron spin resonance investigation of atomic hydrogen centres in γ-irradiated polycrystalline Me(OH)2, where Me ≡ Mg, Ca, Sr, Ba, are reported. Several types of H0-centres having different hyperfine constants, Asub(iso), were obtained in the hydroxides depending on pre-treatment temperature. It has been established that the spin density on the hydrogen nucleus decreases with increasing atomic number of the cation. Analysis of the data obtained was performed using the semiempirical Mulliken-Volsberg-Helmholts molecular orbital method in the supposition that H-atoms occupied interstitials with four OH- ions or three OH- ions and one cation as nearest neighbours. Satisfactory agreement between experimental and calculated values of Asub(iso) was achieved. (author)