弱氢键作用对硫脲水溶液拉曼光谱影响的密度泛函 - ingenta connect.pdf

物理化学学报(Wuli Huaxue Xuebao) November Acta Phys. -Chim. Sin. 2014, 30 (11), 1993-1999 1993 [Article] doi: 10.3866/PKU.WHXB201409011 弱氢键作用对硫脲水溶液拉曼光谱影响的密度泛函理论计算 苏亚琼 吴德印* 田中群 (厦门大学化学化工学院化学系, 固体表面物理化学国家重点实验室, 福建厦门361005) 摘要: 将拉曼光谱和密度泛函理论(DFT)计算结合能够把拉曼谱峰和分子结构及分子间氢键作用之间的变化 联系起来, 反映分子周围的结构信息. 本文通过理论计算水分子和硫脲形成复合物的拉曼光谱, 并结合实验报 道的拉曼光谱, 探究硫脲基频对分子局域结构的依赖性. 通过轨道分析, 发现水分子的氢键作用可以引起硫脲 的前线轨道对易, 这将影响到硫脲的拉曼光谱性质. 最后计算也表明在中性水溶液中由于大的正Gibbs 自由能 变, 硫脲不易发生异构转变. 关键词: 硫脲; 拉曼光谱; 密度泛函理论; 异构转变; 分子间氢键 中图分类号: O641 Density Functional Theory Calculations of the Influence of Weak Hydrogen Bonding Interactions on the Raman Spectra of Thiourea in Aqueous Solution SU Ya-Qiong WU De-Yin* TIAN Zhong-Qun (State Key Laboratory for Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiaman 361005, Fujian Province, P. R. China) Abstract: Raman spectroscopy combined with density functional theory (DFT) calculations provides information at the molecular level to understand weak intermolecular interactions relevant to molecular structures. In this work, the influence of the fundamental properties of thiourea on the Raman spectra of thiourea- water complexes was investigated using DFT calculations. The results showed that hydrogen bond interactions can change the order of the frontier orbitals and directly influence the Raman spectra of thiourea. In addition, the keto-enol tautomerization of thiourea cannot occur in neutral aqueous solution because of the large positive Gibbs free e