双核金属茂合物Zn2(η5-E5)2(E=N, P, As, Sb)电子结构和三阶非线性光学性质的理论研究

运用密度泛函PBE0方法研究了双核金属茂合物Zn2(η5-E5)2(E=N, P, As, Sb)的电子结构, 运用自然键轨道(NBO)方法对该体系的电荷分布及成键特征进行了分析. 此类体系中存在Zn—Zn的σ单键, 为近似纯s成分的成键方式. 用含时密度泛函理论(TDDFT ) 完全态求和(SOS) 方法计算了该体系的三阶非线性光学系数, 结果表明, γ值与最大吸收波长λmax成正比, 在各个分量中, 对〈γ〉起主要贡献的是γzzzz, 最大吸收波长对应的电子跃迁是从Zn—Zn的σ成键轨道到Zn—Zn的σ*反键轨道.

Theoretical Studies on Electronic Structures and Third-order Nonlinear Optical Properties of Di-metallocene Complexes Zn2(η5-E5)2(E=N,P,As,Sb)

Electronic structures of di-metallocene complexes Zn2(η5-E5)2(E=N, P, As, Sb) were investigated with DFT PBE0 method. Charge distribution and bonding characters are analyzed with Natural Bond Orbital(NBO) Theory. The results show that a single σ-bond of Zn—Zn exists in these complexes with a nearly pure s character. The nonlinear third-order polarizabilities(γ) were calculated for the four di-metallocene complexes by time-dependent density functional theory(TD-DFT ) combined with sum-over-states(SOS) method. The calculated results show that γ value is in direct proportion to the maximum absorption wavelength(λmax). Analysis of the main contributions to the third-order polarizability suggests that electron transfer(Zn—Zn σ-bond →Zn—Zn σ*-bond ) along z-axis direction plays a key role in the nonlinear optical response.