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科学通报  2012 

原儿茶酚3,4-双加氧酶复合物中自旋-轨道耦合与零场分裂的计算

, PP. 2842-2848

Keywords: 3,4-PCD-PCA,g-张量,零场分裂(ZFS),自旋-轨道耦合(SOC)

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Abstract:

采用密度泛函理论(DFT)探讨了高自旋原儿茶酚3,4-双加氧酶(3,4-PCD)活化底物儿茶酚(PCA)复合物的磁性电子结构特征及电子轨道起源.计算的g-张量表明,从配体到金属电荷转移(LMCT)主要来自于配体PCA和Tyr408的p型轨道转移电子到Fedp轨道,导致沿x轴方向极化(PCA)或沿y轴方向极化(Tyr408).x和y轴方向的极化要求沿z轴方向,Lz(z=z′),产生较大的自旋轨道耦合(SOC)矩阵元,并且因单中心重原子效应Fe导致gz′=2.0158,即在z'方向较大地偏离于ge=2.0023.由于ΔS=-1自旋翻转激发态混入六重基态,得到较大的零场分裂参数D=+1.147cm-1.SOC计算表明高自旋(S=5/2)基态3,4-PCD-PCA是弱的自旋翻转复合物(SOC=31.56cm-1).

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