Geometric and electronic structure of zwitterionic push-pull polyenes for nonlinear optics
Geometric and electronic structure of zwitterionic push-pull polyenes for nonlinear optics
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DOI：
10.1002/qua.10393
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发表时间：
2003-01-20
影响因子：
2.2
通讯作者：
Bredas, JL
中科院分区：
文献类型：
--
作者：
Geskin, VM;Bredas, JL
我们研究了非线性光学中高极性推拉共轭分子的化学结构，其中纯感应铵/硼酸盐取代基R3N+/BR3-直接或通过苯基连接到可变长度的反式多烯链上。将从头算Hartree-Fock和Moller-Plesset二阶（MP2）方法与混合密度泛函理论（DFT）和半经验（AM1） Hartree-Fock和组态相互作用方法的性能进行了比较。考虑到MP2水平上的电子相关性对于获得可靠的分子几何形状很重要；发现混合DFT （BH和HLYP泛函）的结果与MP2的结果非常接近。用半经验方法得到的一些几何形状与MP2/6-31G结果在定性上不一致。对优化后的结构和取代基效应的性质进行了化学合理化分析。(C) 2002 Wiley期刊有限公司
We present a study of the chemical structure of highly polar push-pull conjugated molecules of interest for nonlinear optics, in which purely inductive ammonium/borate substituents, R3N+/BR3-, are attached to a trans-polyene chain of variable length either directly or via phenyl groups. The performance of ab initio Hartree-Fock and Moller-Plesset second order (MP2) methods is compared with that of the hybrid density functional theory (DFT) and semiempirical (AM1) Hartree-Fock and configuration interaction methods. Taking into account electron correlation at the MP2 level is important to obtain reliable molecular geometries; the hybrid DFT (BH and HLYP functional) results are found to be in close agreement with the MP2 results. Some geometries obtained with the semiempirical methods are in qualitative disagreement with the MP2/6-31G results. A chemical rationalization of the optimized structures and the nature of the substituent effect is proposed. (C) 2002 Wiley Periodicals, Inc.