Electron paramagnetic resonance (EPR) and optical spectral
technique has long been considered as one of the most useful tools
for the experimental and theoretical study of local structure [1,2].
The EPR spectra provides a detailed information of the ground state
of paramagnetic ions and enables one to understand the nature of
the crystal field symmetry produced by the ligands around the cen-
tral metal ion. The optical absorption spectra give the energy level
structure of the central metal ion. EPR and optical studies of the Cu2+
ion doped in a variety of host lattices have been widely investigated
in the literatures [3–5].
The oxide glasses containing transition metal (TM) ions have
potential applications in industry and many allied areas [6]. For
copper-doped Bi2O3-ZnO-B2O3-Li2O (abbr. BZBL) glasses, the EPR
and optical absorption spectra have been measured by Bale and
Rahman [7]. However, until now, the above experimental results
have not been quantitatively explained, and the local structure
of the paramagnetic Cu2+ is not determined, either. Consider-
ing the local structure around the Cu2+ site would be helpful in
understanding the properties of glasses. Furthermore, theoretical
investigations on the relation between these spectra (EPR and opti-
cal spectra) and the local structure are of fundamental and practical
significance. In this work, the EPR (g factors and hyperfine structure
parameter A) and the local structure of the BZBL: Cu2+ glasses are
theoretically studied using the three-order perturbation formulas
of EPR parameters for a 3d9 ion in an tetragonal elongated octahe-
dron. In the calculations, the local tetragonal distortion of the Cu2+
site is quantitatively determined from the superposition model in
view of the Jahn–Teller effect.