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Semiempirical prediction of the hyperpolarizabilities for cyanovinyl‐substituted donor‐acceptor molecules
Author(s) -
CunYuan Zhao,
Yong Zhang,
WeiHai Fang,
XiaoZeng You
Publication year - 1996
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19960140503
Subject(s) - chemistry , molecule , acceptor , conjugated system , computational chemistry , chemical physics , organic chemistry , polymer , quantum mechanics , physics
Abstract We present here a systematically theoretical study on the nonlinearities and their structure‐property relationship of cyanovinyl‐substituted donor‐acceptor molecules by virtue of semiempirical PM3/AM1‐FF approach. Good consistency between measured and calculated hyperpolarizabilities is obtained. Results show that conformation has a significant effect on hyperpolarizabilities. The torsion angle change between two conjugated parts of the molecular systems can substantially alter the nonlinearities. The total amount of charge transfer difference from donor to acceptor has been introduced to understand the microscopic nature of the nonlinear optical properties for the title molecules. General guidelines may be sought out in the search of molecules with large values of β. Some molecules with large molecular hyperpolarizabilities can be predicted by the optimization for the longer δ‐electron systems with both acceptor and donor groups.