氢键对2-(N-甲基)氨基-5-硝基吡啶分子非线性光学性质的影响

Hydrogen bonding effects on the nonlinear optical properties of 2-(N-methyl) amino-5-nitropyridine molecule

本文在杂化密度泛函理论水平上研究了溶剂对2-(N-甲基)氨基-5-硝基吡啶分子非线性光学性质的影响.在溶剂中,构造了包括氢键作用的超分子体系,在优化结构的基础上分别研究了由极化连续模型模拟的溶剂与该分子的长程相互作用、溶剂与该分子的氢键相互作用以及溶剂与包括氢键作用的超分子体系整体的相互作用对分子的几何结构、非线性光学性质、紫外吸收光谱和电荷分布等特性的影响.结果表明,溶剂中分子电偶极矩、线性极化率和第一超极化率都增大,而溶剂与溶质分子通过氢键形成的超分子结构与单体有着明显区别.因此,氢键对分子结构和性质的影响较大,从而将明显的影响该类分子的非线性光学性质.

The solvent effect on the nonlinear optical （NLO） properties of 2-（N-methyl） amino-5-nitro- pyridine molecule was studied on the base of the hybrid density functional theory, The supermolecular structures of the solute and the solvent molecules connected by hydrogen bonding have been constructed. The solvent ef- fects on the solute molecular geometrical structures, NLO properties, ultraviolet spectra and charge distributions have been investigated by considering long range interaction simulated by polarisable continuum model （PCM）, the hydrogen bonding interactions, and the supermoleculars with the solvent molecules. It is shown that polarity solvents have much influence on the molecular geometrical structures. And the dipole moment, the polarizabilities, the first-order nonlinear hyperpolarizabilities increased rapidly in solvent. On the other hand, the geometrical structures, ultraviolet spectra and NLO properties of supermolecular have been changed significantly comparing with monomer. As a result, the hydrogen bonding interaction may induce a large variation of the structures and NLO properties of molecules. So the hydrogen bonding interaction must be considered when we try to calculate the molecular first-order nonlinear hyperpolarizabilities in solvents.