Investigations of the electron paramagnetic resonance parameters and the tetragonal local structure for (VCl₆)^4- coordination complex in MCl:V²⁺ (M=Na, K, Rb) systems

By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120\times 120 complete energy matrix, this paper determines the local lattice structure parameters R_1 and R_2 for MCl:V^2 + (M=Na, K, Rb) systems at 77 K, 195 K and RT (room temperature 295 K or 302 K), respectively. The theoretical results indicate that there exists a compressed distortion in MCl:V^2 + systems. Meanwhile, it finds that the structure parameters R_1 , R_2 and \left| \Delta R \right| ( = R_1 - R_2 ) increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. \Delta R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed.