Microscopic Structure of Strongly Hydrogen-Bonded Solutions

本文用X射线、中子衍射、拉曼散射和红外吸收等方法研究了高浓度HOI、HBr、HNO_3和H_3PO_4水溶液中的分子间氢键结构。部分结构因子由H/D同位素取代的21mol%HCl和36mol%HNOO_3水溶液的中子衍射数据确定。最近邻O的距离非常短。H和O在21mol%HCl溶液中，氧离子与水分子形成强氢键，形成H_5O_2结构单元。用X射线衍射法研究了浓HCl和HBr水溶液中分子间结构的浓度依赖性。红外双差技术应用于浓盐酸水溶液。用Q-D谱带分析了HDO分子的非耦合O-D伸缩振动带。在H_3O^+的第一水化壳层中，HDO分子的O-D伸缩带位于-2400 cm ~ 2处<-1>。用X射线衍射、低频各向同性拉曼散射和红外双差谱研究了高浓度水溶液中Na^+的水合结构。

X-ray, neutron diffraction, Raman scattering and Infrared absorption measurements were carried out for highly concentrated aqueous HOI, HBr, HNO_3 and H_3PO_4 solutions in order to investigate intermolecular hydrogen-bonded structure in acidic solutions. Partial structure factors were determined from neutron diffraction data obtained for H/D isotopic substituted aqueous 21 mol% HCI and 36 mol% HNOO_3 solutions. Extremely short distances were determined for the nearest neighbor O..H and O...O correlations in the 21 mol% HCI solution, suggesting that the oxonium ion forms a strong hydrogen bond between the nearest neighbor water molecule to form H_5O_2 structure unit. Concentration dependence of intermolecular structure in concentrated aqueous HCI and HBr solutions was investigated by X-ray diffraction measurements. Infrared double-difference technique was applied for concentrated aqueous HCI solutions. The uncoupled O-D stretching vibrational band was analized in terms of the Q-D band for ion-affected and for bulk HDO molecules. The O-D stretching band for HDO molecule in the first hydration shell of H_3O^+ was found at-2400 cm^<-1>. The hydration structure of Na^+ in highly concentrated aqueous solutions was also investigated by X-ray diffraction, low-frequency Isotropic Raman scattering and IR double-difference methods.