Electron Paramagnetic Resonance of [Cu3+–Cu2+](C2v) Impurity Dimers inside a BaF2:Cu Ionic Crystal.

[Cu³⁺–Cu²⁺] (С_2v) impurity dimers with antiferromagnetic coupling between copper ions form inside synthesized BaF₂ crystals. The molecular structure of the synthesized dimers is studied via electron spin resonance at frequencies of 9.3 and 34.2 GHz in the 5–150 K range of temperatures. It is shown that ⁶³Cu³⁺ and ⁶³Cu²⁺ ions replace the neighboring Ва²⁺ cations in the lattice with the formation of a dimer with a bond axis parallel to one of the 〈110〉 crystallographic axes. It is found that copper ions in the synthesized dimer are coupled by antiferromagnetic exchange, and its ground inverse state is a doublet with spin S = 1/2. The parameters of the electron Zeeman interaction, some parameters of hyperfine and quadrupole interaction between ⁶³Cu³⁺ and ⁶³Cu²⁺ ions, and some parameters of the ligand's hyperfine interaction with two equivalent F^– ions are determined. [ABSTRACT FROM AUTHOR]