title: EPR parameters and local geometry for Cr3+ and V2+ ions in HfS2 crystals.
abstract: From the high-order perturbation formulas of EPR parameters (zero-field splitting D, g factors gparallel, gperpendicular and hyperfine structure constants Aparallel, Aperpendicular) based on the two spin-orbit coupling parameter model for 3d3 ions in trigonal symmetry, the EPR parameters of Cr3+ and V2+ ions in HfS2 crystals are calculated. From the calculations, it is found that the local trigonal distortion angle theta of impurity center in HfS2:Cr3+ is smaller than that in HfS2:V2+. The dominant cause of the small zero-field splitting |D| and g-anisotropy |Deltag|=|gparallel-gperpendicular| in HfS2:Cr3+ (compound to HfS2:V2+) is due to the small local trigonal distortion angle theta rather than to the small impurity-ligand distance R in HfS2:Cr3+.
authors.affiliation: Department of Material Science, Sichuan University, Chengdu 610064, PR China.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Qing
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wen-Chen
authors.forename: Wu
authors.initials: W
authors.lastname: Xiao-Xuan
authors.forename: Mei
authors.initials: M
authors.lastname: Yang
mesh_terms: D002857:Chromium / Q000737:chemistry*; D003460:Crystallization; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D007477:Ions / Q000737:chemistry; D008956:Models, Chemical; D013457:Sulfur Compounds / Q000737:chemistry*; D014639:Vanadium / Q000737:chemistry*
chemical_list: D007477:Ions; D013457:Sulfur Compounds; D014639:Vanadium; D002857:Chromium