Effects of additives on the e.s.r. of zinc oxide

Abstract

Solutions of various organic compounds were mixed with zinc oxide powder. The mixtures of these compounds with zinc oxide were prepared by evaporating the solvent. When the zinc oxide with any of the additives is heated at 300 °C, two e.s.r. lines with g factors of 1.960 and 2.004, named l1 and l2, were observed. The intensities of l1 and l2 come to their equilibrium values after several minutes of heating. The results show that l1 and l2 are not from two independently existing species but from the two species R1 and R2, whose concentrations are connected with each other by some competitive equilibrium reactions. It was not possible to estimate the two equilibrium constants separately, but their product was estimated to be less than 2.5 × 10−8. R1 is concluded to be Zni+ (interstitial), while R2 may be Zn+ or (ZnOv)−(2v−1), where v is an integer. The compounds which gave strong l2 were naphthoquinones, naphthols, benzoquinone, hydroquinone, and anthraquinone, while the compounds which gave strong l1 were benzoin, anthrone, pyrene, and naphthalene.