四角对称晶场中~4B_1(3d^3)态离子的磁相互作用及其自旋哈密顿参量研究

Investigations of magnetic interactions and spin-Hamiltonian parameters for ~4B_1(3d^3) state ion in a tetragonal crystal field

基于完全对角化方法,研究了~4B_1(3d^3)态离子在四角对称晶场中的磁相互作用,分析了自旋哈密顿参量(b02,g∥,g⊥,Δg)的微观起源.结果表明在被考虑的大部分晶场区域,人们通常考虑的SO(spin orbit)磁相互作用的贡献最为重要;然而,对于零场分裂参量b02而言,来自其他机理(包括SS(spin orbit),SOO(spin other orbit),SO SS SOO)的贡献在大部分晶场区域超过了20%;在部分晶场区域,其他机理的贡献甚至超过SO机理的贡献.详细地分析了Macfarlane零场分裂参量b02近似三阶微扰理论的收敛性,结果表明该理论在大部分晶场区域收敛性较差.讨论了3d3态离子第一激发态2Eg分裂的微观起源.并利用群论方法解释了在C4v和C3v对称晶场中2Eg态分裂的不同机理.

The magnetic interactions as well as the microscopic origins of the spin-Hamiltonian (SH) parameters including b20, g parallel , g perpendicular , Δg for 4B1(3d3) state ion in a tetragonal crystal field have been investigated using the complete diagonalization method (CDM). It is found that the contribution to the spin-Hamiltonian parameters arising from the spin-orbit (SO) magnetic interaction is the most important for most part of the crystal field (CF) ranges. However, the contributions to the zero-field split (ZFS) parameter b20 from the other three mechanisms including the SS mechanism and SOO mechanism as well as SO-SS-SOO combined coupling mechanism exceed 20% for most part of the CF ranges, especially for some CF ranges, in which the contributions to the ZFS parameter b20 from the other three mechanisms exceed that from the SO mechanism. It is shown in present studies that the approximate expression of ZFS parameter b20 developed by Macfarlane is not convergent for most part of the CF ranges. The microscopic origins of the splitting in the lowest existing state 2Eg are studied. Different mechanisms of the splitting 2Eg state for C4v and C3v crystal fields are explained using group theory.