Prediction and interpretation of the 57Fe isomer shift in Mossbauer spectra by density functional theory
Prediction and interpretation of the 57Fe isomer shift in Mossbauer spectra by density functional theory
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DOI：
10.1016/s0020-1693(02)01031-9
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发表时间：
2002-09-26
影响因子：
2.8
通讯作者：
Neese, F
中科院分区：
文献类型：
--
作者：
Neese, F
本文报道了两种常用的密度泛函方法（B3LYP和BP 86）在Fe-57穆斯堡尔谱（MB）同质异能位移（IS）预测中的应用。非相对论计算的理论电子密度和实验测量的IS之间的线性相关性的建立。这两种泛函导致MB IS的准确预测，在约2 mm s（-1）的范围内，标准偏差约为0.1 mm s（-1）。不同的总电荷，总自旋，在铁的价态，配位数和配位几何形状的配合物的相关性。对IS的贡献进行了详细分析。结果表明，重要的贡献是：（a），3s-贡献的变化，这主要是由于不同的屏蔽根据d-布居的金属;和（B）的变化在价层的贡献。后者的贡献约占70%的总观察到的变化。价贡献的解释是复杂的，涉及共价变化的贡献，由于成键和屏蔽效应的轨道扭曲。金属-配体距离的变化也是一个重要因素，它影响4s轨道的形状，从而调节IS。(C)2002 Elsevier Science B.V.保留所有权利。
The calibration of two popular density functionals (B3LYP and BP86) for the prediction of isomer shifts (IS) in Fe-57 Mossbauer (MB) spectra is reported. A linear correlation between non-relativistically calculated theoretical electron densities and experimentally measured ISs is established. Both functionals lead to accurate predictions of MB ISs with standard deviations on the order of approximately 0.1 mm s(-1) over a range of approximately 2 mm s(-1). The correlation holds for complexes of different total charge, total spin, valence state at the iron, coordination number and coordination geometry. A detailed analysis of the contributions to the IS is presented. It is shown that the important contributions are: (a),the variation of the 3s-contribution which is mainly caused by differing shielding according to the d-population of the metal; and (b) variations in the valence shell contribution. The latter contribution accounts for approximately 70% of the totally observed variation. The interpretation of the valence contribution is complex and involves contributions from changes in covalencies, orbital distortions due to bonding and shielding effects. The changes in metal-ligand distances are also an important factor, which influences the shape of the 4s-orbital and therefore modulates ISs. (C) 2002 Elsevier Science B.V. All rights reserved.