E.S.R. Investigation of 3d⁹ Ions in Alkali-Halides

Abstract

Cu²⁺ in NaCl, LiCl and NaF, and Ni⁺ in NaCl, most of which were produced from Cu⁺ and Ni²⁺ by X-ray irradiation were studied by the e.s.r.
All of Cu²⁺ had elongated tetragonal surroundings, while Ni⁺ had compressed ones. In NaCl:Cu²⁺, the optical dichroism along a cube edge was detected at 5 K corresponding to the Jahn-Teller distortion.
From the observed super hyperfine structure of surrounding nuclei the amounts of covalency, f_s and f_σ were estimated as 0.77 to 0.89% and 7.9 to 12% in the chlorides, respectively.
In the case of NaCl:Cu²⁺ doped as divalent states, sharp anisotropic spectra without the hyperfine structure due to Cu nucleus were observed, which are presumably due to coagulated ions.