Theoretical explanation of electron paramagnetic resonance spectral data in vanadyl doped CdNaPO4·6H2O crystal

Theoretical studies on the electron paramagnetic resonance parameters for the tetragonal VO2+ center in CaO-Al2O3-SiO2 system

“…Our calculations indicate that both signs of A and A ⊥ are negative, this point is in accordance with the Ref. [7] and also be supported by the theoretical results for V 4+ ions in many crystals [1,13,26] and glasses [20,25]. In fact, from the formulae of A constants (Eqs.…”

“…1) for the planar ligands may lead to more V 4+ 3d-3s admixture and hence the larger κ. In addition, many previous works suggest that κ is within the range 0.6-1.0 for V 4+ (or VO 2+ ) ions in various crystals and glasses [1,2,13,20,25,26]. The value of κ(≈ 0.84) adopted in this work lies within the range and can be regarded as rational.…”

Theoretical studies of the optical and EPR spectra for VO^{2+} in Na_{3}C_{6}H_{5}O_{7}·2H_{2}O single crystal

“…this is consistent with a number of theoretical investigations [4,9,[19][20][21][22] and the previous calculation [11]. Therefore, the above calculated A and A ⊥ of the hyperfine structure constants for TSCD:VO 2+ are reasonable in signs and in magnitude.…”

“…Thus, the g factors, especially the anisotropy ∆g (= g ∥ − g ⊥ ) is connected with the tetragonal field parameters and hence with the local structure (i.e., the relative tetragonal elongation R ∥ − R ⊥ ) of the studied systems. Due to the covalence reduction effect for 3d n ions in crystals, we have [19][20][21][22] ζ = N 2 ζ 0 and P = N 2 P 0 .…”

“…A 2 (R) and A 4 (R) are the intrinsic parameters with the reference distance R, where R (≈ R ⊥ ≈ 1.985 Å [17]) is taken for the VO 2+ in cubic field. For 3d n ions in octahedra, the ratio A 2 (R)/A 4 (R) is in the range of 9-12 in many crystals [4,12,13,[18][19][20]. Here, we take the mean value, i.e.…”