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Density Functional Theory Investigation on the Second‐Order Nonlinear Optical Properties of Chlorobenzyl‐ o ‐Carborane Derivatives
Author(s) -
Liu Yan,
Yang Guochun,
Sun Shiling,
Su Zhongmin
Publication year - 2012
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.201200514
Subject(s) - hyperpolarizability , chemistry , density functional theory , nonlinear optical , atomic orbital , computational chemistry , molecular orbital , carborane , aryl , electron , nonlinear system , stereochemistry , molecule , organic chemistry , quantum mechanics , physics , alkyl , polarizability
The structures and second‐order nonlinear optical (NLO) properties of a series of chlorobenzyl‐ o ‐carboranes derivatives ( 1 – 12 ) containing different push‐pull groups have been studied by density functional theory (DFT) calculation. Our theoretical calculations show that the static first hyperpolarizability ( β tot ) values gradually increase with increasing the π‐conjugation length and the strength of electron donor group. Especially, compound 12 exhibits the largest β tot (62.404×10 −30 esu) by introducing tetrathiafulvalene (TTF), which is about 76 times larger than that of compound 1 containing aryl. This means that the appropriate structural modification can substantially increase the first hyperpolarizabilities of the studied compounds. For the sake of understanding the origin of these large NLO responses, the frontier molecular orbitals (FMOs), electron density difference maps (EDDMs), orbital energy and electronic transition energy of the studied compounds are analyzed. According to the two‐state model, the lower transition energy plays an important role in increasing the first hyperpolarizability values. This study may evoke possible ways to design preferable NLO materials.