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首页> 外文期刊>Polyhedron: The International Journal for Inorganic and Organometallic Chemistry >Antisymmetric double exchange and zero-field splittings in mixed-valence clusters
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Antisymmetric double exchange and zero-field splittings in mixed-valence clusters

机译：混合价簇中的反对称双交换和零场分裂

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The effect of an antisymmetric double exchange (AS DE) interaction in the mixed-valence (MV) dimeric d(n)-d(n+1) and trimeric d(n)-d(n)-d(n+1) clusters of orbitally non-degenerate ions is considered. In the dimeric clusters, strong isotropic Anderson-Hasegawa (AH) DE and Heisenberg exchange interactions (t-J model) form isotropic DE states E+/- (0)(S). In the MV dimers, the Moriya spin-flop hopping, which is determined by the spin-orbit coupling, is described by the effective Hamiltonian of an AS DE interaction H-ASDE = 2iK(ab)T(ab)(S-b-S-a), where K-ab = -K-a is a real AS vector coefficient, T-ab is the isotropic transfer operator. The operator H-ASDE has a form of the spin-transfer interaction. Analytical expressions for the matrix elements of HASDE were obtained for d(n)-d(n+1) clusters. The AS DE matrix elements depend on the projection M of S. AS DE mixes the AH DE states E-+(0)(S) and E--(0)(S) with the same S of the different parity. The AS DE coupling and the Dzialoshinsky-Moriya (DM) AS exchange (H-DM = G(ab)[S-a x S-b]) mix the AH states with different S of the same parity. AS DE forms the effective spin S'. In the d(1)-d(2) and d(9)-d(8) clusters, the AS DE contributions to the zero-field splitting (ZFS) parameters are different for the AH high-spin states E+(3/2) and E-(3/2). An AS DE leads to non-collinear orientation of spins in the MV pair and anisotropy of g-factors. An anisotropic DE contributes to ZFS. In the trimeric MV clusters, the isotropic DE forms the isotropic trigonal (2S+1)Gamma terms, Gamma =A(1), A(2), E. The AS DE results in the new effect: the linear fine splittings Delta of the degenerate E2S+1 DE terms. The fine splittings Delta are proportional to the AS DE parameter K-Z = (K-ab(Z) +K-bc(Z) +K-ca(Z))/3 of the MV trimer. The vector of the AS DE interaction K-Z is directed along the trigonal Z-axis of the MV trimer. The AS DE mixes the (2S+1)A(1) and (2S+1)A(2), E2S+1 and E2S+1 DE terms (DeltaS = 0, 1). In the trimeric MV clusters with high individual spins si, the AS DE and DM AS exchange mixing of the DE levels (2S+1)Gamma determines the contributions of the second order to the ZFS parameters D-S, which are different for the A(i) and E DE terms. For the [Cu(II)Cu-2(I)] delocalized cluster, the AS DE ZFS Delta = 2K(Z)root3of the ground E-2 DE term determines strong anisotropy of the Zeeman splittings, anisotropy of g-factors (g(Z) not equal 0, g(X,Y) = 0) and magnetic properties. (C) 2003 Elsevier Science Ltd. All rights reserved. [References: 54]
机译：反对称双交换（AS DE）相互作用在混合价（MV）二聚体d（n）-d（n + 1）和三聚体d（n）-d（n）-d（n + 1）中的作用考虑轨道上非简并离子的簇。在二聚体簇中，强的各向同性的Anderson-Hasegawa（AH）DE和Heisenberg交换相互作用（t-J模型）形成各向同性的DE状态E +/-（0）（S）。在MV二聚体中，由自旋轨道耦合确定的Moriya自旋跳变由AS DE相互作用的有效哈密顿量H-ASDE = 2iK（ab）T（ab）（SbSa）描述，其中K-ab = -Ka是真实的AS矢量系数，T-ab是各向同性传递算子。算子H-ASDE具有自旋转移相互作用的形式。获得了d（n）-d（n + 1）簇的HASDE矩阵元素的解析表达式。 AS DE矩阵元素取决于S的投影M.AS DE将AH DE状态E-+（0）（S）和E-（0）（S）与相同奇偶性的S混合在一起。 AS DE耦合和Dzialoshinsky-Moriya（DM）AS交换（H-DM = G（ab）[S-a x S-b]）将AH状态与相同奇偶校验的不同S混合在一起。 AS DE形成有效自旋S'。在d（1）-d（2）和d（9）-d（8）聚类中，对于AH高旋转状态E +（3 / 2）和E-（3/2）。 AS DE导致MV对中自旋的非共线取向和g因子的各向异性。各向异性DE有助于ZFS。在三聚体MV簇中，各向同性的DE形成各向同性的三角（2S + 1）Gamma项，Gamma = A（1），A（2），E。AS DE产生了新的效果：线性细分裂Delta简并的E2S + 1 DE项。细分裂Delta与MV三聚体的AS DE参数K-Z =（K-ab（Z）+ K-bc（Z）+ K-ca（Z））/ 3成正比。 AS DE交互作用K-Z的向量沿MV三聚体的三角Z轴定向。 AS DE混合了（2S + 1）A（1）和（2S + 1）A（2），E2S + 1和E2S + 1 DE项（DeltaS = 0，1）。在具有高自旋si的三聚体MV群集中，DE级别（2S + 1）的AS DE和DM AS交换混合Gamma确定了二阶对ZFS参数DS的贡献，这对于A（i ）和E DE条款。对于[Cu（II）Cu-2（I）]离域团簇，地面E-2 DE项的AS DE ZFS Delta = 2K（Z）root3确定Zeeman分裂的强各向异性，g因子的各向异性（g （Z）不等于0，g（X，Y）= 0）和磁性。 （C）2003 Elsevier ScienceLtd。保留所有权利。 [参考：54]

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