Theoretical studies of the optical and EPR spectra for vanadyl ions in alkaline-earth aluminoborate glasses

Theoretical investigation of EPR and optical spectra of Mo(V) in [Mo6O19][N(C4H9)4]3 salt

“…In the present work, two bands (11,600 and 20,400 cm À 1 ) of the assignments are, respectively, 2 B 2g -2 B 1g and 2 B 2g -2 A 1g transitions. The d-d transitions obtained from the above calculations are consistent with many research results for a d 1 ion in tetragonally compressed octahedron [18][19][20][21] and can be regarded as rational. g factors varied with the R J as shown in Fig.…”

“…1, the effect of an Table 2 octahedral environment on the d orbitals of a TM ion may be treated as a splitting of the original group of five orbitals into three lower 2 T 0 2g and two upper 2 E 0 g orbitals under cubic field. There are many reports on the C 4v crystal field [18][19][20][21], the 2 T 2g level is further split into 2 B 2g (9d xy S) and 2 E g (9d xz S, 9d yz S) levels, and 2 E 0 g level into 2 B 1g (9d x 2 Ày 2 S)and 2 A 1g (9d z 2 S) levels. Thus, the assigned transitions of the literature [6] may be inaccurate.…”

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 investigation for the EPR g-factors of the mixed ground state in NaCl: Ag2+ crystals

“…The EPR g factors of these tetragonal Ag 2+ centers in NaCl crystals were measured from the studies [4]. Theoretically, the classical crystal-field theory has been extensively applied to study EPR spectra of the ionic compounds [5][6][7][8]. However, the influence of the covalence on magnetic properties is not taken into account in classical crystalfield theory.…”