Molecular orbital closed loops analysis of the third-order NLO response of polyanion [M8O26]4− (M = Cr, Mo, W): a TDDFT study
Molecular orbital closed loops analysis of the third-order NLO response of polyanion [M8O26]4− (M = Cr, Mo, W): a TDDFT study
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聚阴离子 [M8O26]4− (M = Cr, Mo, W) 三阶 NLO 响应的分子轨道闭环分析：TDDFT 研究
DOI：
10.1007/s11224-013-0313-2
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发表时间：
2014
影响因子：
1.7
通讯作者：
Libin Niu
中科院分区：
文献类型：
--
作者：
Fujun Li;Xiao;Rongjian Sa;Libin Niu
利用分子轨道闭环理论对聚氧乙烯醚笼型结构的三阶非线性光学响应进行了TDDFT研究。用密度泛函/时间分辨傅里叶变换（DFT/TDDFT）方法系统地研究了三种VIB族八聚氧乙烯酸盐阴离子团簇β-[Cr 8 O26] 4-，β-[Mo 8 O26]4-和β-[W8 O26]4-的三阶非线性光学性质.基于β-[Mo 8 O26]4−离子的晶体学几何结构和热稳定性，采用DFT方法分别模拟了β-[Cr 8 O26]4−和β-[W8 O26] 4 −的几何结构，并采用有限场方法计算了二阶静态超极化率γiiii，γiijj和γmean，作为通常DFT能量运行的扩展，结果表明，在没有配体的情况下，三种簇合物均具有较大的超极化率，且配合物中的铬酸根离子具有比铬酸根离子和钨酸根离子大得多的非线性光学响应.为了找出同族金属的三种聚氧乙烯酸盐超极化率差异较大的原因，还用密度泛函方法研究了它们的电子性质，讨论了非线性光学响应的起源，特别是，分析了电子结构变化对非线性光学响应的影响机理，并用分子轨道“闭合环”来表示该理论通常用于估计聚氧乙烯酸盐阴离子笼的热稳定性和氧化还原能力。图形摘要在没有任何配体的配位下，聚阴离子[M8 O26]4-（M = Cr，Mo，W）在高对称结构中表现出中等程度的三阶非线性光学响应，甚至高于一维金属-金属键合化合物Cr（II）4、Mo（II）4和一些C60衍生物。介绍了一种新的分子“轨道环”的思想，用于非线性光学响应机理的理论探讨，并将其应用于聚阴离子，证明是一种有效的分析方法。
Molecular orbital closed loops theory was used to explain the mechanism of the third-order nonlinear optical (NLO) response of polyanion cage structure of polyoxometalate by TDDFT study. The third-order NLO properties of three octa-polyoxometalate anion clusters of VIB group metals, β-[Cr8O26]4−, β-[Mo8O26]4−, and β-[W8O26]4−, were studied by DFT/TDDFT method systematically. The geometric structures of β-[Cr8O26]4− and β-[W8O26]4− were separately simulated by DFT method, based on the crystallographically determined geometry of the β-[Mo8O26]4− ion, and the thermo stability, and the second static hyperpolarizabilities, γiiii, γiijj, and γmean were calculated by finite-field method as an extension of the usual DFT energy run, and the results suggest that with no ligands coordinated, all of the three clusters possess moderately large hyperpolarizabilities, and the molybdate ion possess much larger NLO response than the chromate and the tungstate ions. In order to find out the reason of the big difference in the hyperpolarizabilities of the three polyoxometalates of the same group metals, the electronic properties were also studied by DFT method for the discussion of the origination of the NLO response, specially, the mechanism of the electronic structure change affecting the NLO response is analyzed and exhibited by the molecular orbital “closed loops” theory which has usually been used to estimate the thermo stability and redox ability of the polyoxometalate anion cages.Graphical abstractWithout the coordination by any ligands, polyanion [M8O26]4− (M = Cr, Mo, W) in high symmetry structures present moderately high third-order NLO response by TDDFT study, even higher than the one-dimensional metal–metal bond compounds Cr(II)4, Mo(II)4, and some C60 derivatives. A new thought of molecular “orbital loops” for the theoretical exploration of the mechanism of NLO response were introduced, and applied to the polyanions and proved to be an effective analyzing method .
影响因子：
16.6
作者：
Mal, SS;Kortz, U
通讯作者：
Kortz, U