晶体中过渡金属离子零场分裂参量的微观解释II:微观机制与实例

讨论了晶体中过渡金属离子零场分裂产生的各种微观机制,并给出了多个实例。结果表明,过去工作通常忽略的自旋-自旋相互作用机制,以及自旋-轨道与自旋-自旋联合作用机制,在一些特殊情况下是不可忽略的。计算还表明：高激发态的贡献通常是重要的。

Microscopic Interpretation of the Zero-field Splitting Parameters of Transition-metal Ions in Crystals II:Mechanisms and Illustrations

On the basis of the effective Hamiltonian theory presented in Part I(J. Sichuan Normal Univ.,2002,25(6):606～614), an investigation is made part for the individual contributions to the zero-field splitting parameters from the spin-orbit (SO) and the spin-spin (SS) couplings, respectively, and from the combined effect of these two interactions; these are accordingly called SO, SS, and SO-SS mechanisms, respectively. Illustrative evaluations are then carried out for Mn2+(6S,3d5) ions in cubic fields, a Cr3+(4F,3d3) ion at the C3 symmetry Nb-site in LiNbO3 crystals, and a Fe2+(5D,3d6) ion in a trigonal field. As a general consequence, the SS and the SO-SS mechanisms, which are often omitted in early works, are found non-negligible in comparison with the dominant SO mechanism. The calculated results also show the importance of high-lying states.