Theoretical Insight into the Second-Order NLO Response of the Bis{4-[2-(4-pyridyl)ethenyl]benzoato}-zinc(II) Metal鈥揙rganic Framework
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- 作者：Yuexing Zhang ; Beno卯t Champagne
- 刊名：The Journal of Physical Chemistry C
- 出版年：2012
- 出版时间：October 18, 2012
- 年：2012
- 卷：116
- 期：41
- 页码：21973-21981
- 全文大小：371K
- 年卷期：v.116,no.41(October 18, 2012)
- ISSN：1932-7455
文摘
Ab initio wavefunction and density functional theory calculations have been performed to investigate the second-order nonlinear optical (NLO) properties of the bis{4-[2-(4-pyridyl)ethenyl]benzoato}-zinc(II) metal鈥搊rganic framework (MOF). This has been carried out by adopting the supramolecular or cluster approach, which consists in analyzing the evolution of the first hyperpolarizability as a function of the number of units of the system. In a first step, the impact of the method of calculation has been assessed, evidencing that the exchange-correlation functional has a stronger impact on the first hyperpolarizability (尾) values than the basis set. Still, the first hyperpolarizability values related to the hyper-Rayleigh scattering (HRS) (尾HRS) are slightly more sensitive to the Zn basis set than to that of the other atoms, but the combination of the LANL2DZ basis for Zn with the 6-31G* basis set for the other atoms provides stable results with respect to adding supplementary valence, polarization, and diffuse functions as demonstrated by the variations of 尾HRS that remain smaller than 6%. Several structure/property relationships have then been deduced for the 尾 of this MOF: (i) the lack of coordination of the ligands extremities enhances 尾 because their donor/acceptor characters are not damped by the Zn2+ cations, (ii) the 尾 of clusters expanding in one direction increases almost linearly with the cluster size, (iii) the deviations with respect to linearity are smaller than 25%, which differ from organic molecular crystals, and (iv) the octupolar component of the 尾 response is of the same order of magnitude as its dipolar counterpart, and its relative importance generally increases with the cluster size.