Abstract：As an important model system, 3d1 ions (VO2+, V4+ et al) have been extensively investigated by means of electron paramagnetic resonance (EPR), and many experimental results of EPR parameters were also measured. The optical absorption and EPR parameters (g factors g‖, g⊥ and hyperfine structure constants A‖, A⊥) of a tetragonal V4+ center in zinc phosphate glass are theoretically investigated, using the perturbation formulas for a 3d1 ion in tetragonally compressed octahedra. Since the spin-orbit coupling parameter ζ0p(≈150 cm-1) of ligand O2- is close to that ζ0d(≈248 cm-1) of the central 3d1 ion in zinc phosphate glass doped VO2+, the effect of the spin-orbit coupling parameter ζp0 on the EPR spectra and optical absorption spectra should be taken into account. In this work, the relationship between the EPR parameters as well as the optical absorption spectra and the local structure of the impurity center are established based on the superposition model. By fitting the calculated EPR parameters and optical absorption spectra for V4+ center in zinc phosphate glass to the experimental data, the local structure parameters of [VO6]8- cluster are obtained. According to the investigation, the magnitudes of the metal-ligand distances parallel and perpendicular to the C4-axis of [VO6]8- cluster are, respectively, R‖≈0.175 nm and R⊥≈0.197 nm, the local structure around the V4+ ions possesses a compressed tetragonal distortion along C4 axis. Theoretical results of EPR parameters and optical absorption spectra are in good agreement with experimental data, the validity of the calculated results has also been discussed. Thus，perturbation method is effective to the studies the EPR parameters and optical spectra of transition-metal 3d1 ions in crystals. In addition, based on the studies of the hyperfine structure constants (A‖ and A⊥), one can found that the large value of κ indicates a large contribution to the hyperfine constant bv the unpaired s-electron.
Key words：EPR;Superposition model;Two-spin-orbit-coupling parameter model;VO2+ ion
李超英，黄先恺，涂 虬，王伟杨，郑雪梅 . 锌磷酸盐玻璃掺杂VO2+吸收光谱和EPR谱研究 [J]. 光谱学与光谱分析, 2015, 35(07): 1808-1811.
LI Chao-ying, HUANG Xian-kai, TU Qiu, WANG Wei-yang, ZHENG Xue-mei . Theoretical Investigation of the Electron Paramagnetic Resonance Parameters and Local Structures for Zinc Phosphate Glass Doped with VO2+. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2015, 35(07): 1808-1811.
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