盐对甲醇微观结构的影响.pdf

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1、物理化学学报(WuliHuaxueXuebao)SeptemberActaPhys．一Chim．Sin．，2010，26(9)：2473-24802473(ArticleJwww．whxb．pku．edu．cn盐对甲醇微观结构的影响余小春林珂胡乃银周晓国刘世林(中国科学技术大学化学物理系，合肥微尺度物质科学国家实验室(筹)，合肥230026)摘要：利用拉曼光谱研究盐对甲醇微观结构的影响．比较了不同盐／甲醇体系的()_一H伸缩谱段和c—0伸缩谱段的超额拉曼光谱，对比给出了阴、阳离子与甲醇的相互作用．0～H

2、伸缩谱段的超额拉曼光谱明显地显示了阴离子与甲醇形成弱氢键，氢键强度排序为CH。OH—CH。OH>C1--CH。OH>NOi—CHzOH>C102一CH。OH，在这个波段内，基本观察不到阳离子与甲醇的相互作用．在c～0伸缩谱段内，阴阳离子均有显著的体现，且与它们作用的甲醇c一0伸缩振动频率有如下的关系：cH厂0H(阴离子)

3、～0．005)下离子对第一溶剂化层以外的甲醇氢键网络结构没有明显影响．关键词：拉曼光谱；阴离子；阳离子；甲醇；第一溶剂化层中图分类号：0645EffectsofSaltsontheMicrostructureofMethanolYUXiao—ChunLINKeHUNai—YinZHOUXiao—GuoLIUShi—LintHefeiNationalLaborato~forPsicalSciencesattheMicroscale,DepartmentofChemicalPsics,Universityo

4、fScienceandTechnologyofChina,Hefei230026,P．R．China)Abstract：Westudiedtheeffectsofsaltsonthemicrostructureof1iquidmethanolusingtheRamanspectra．WecomparedtheexcessRamanspectraofdifferentmethanolicsaltsolutionsinthe0～HandC—Ostretchingregions．Theseregionsref

5、lecttheinteractionsbetweenanions(cations)andmethanolmolecules．IntheHstretchingregion．theexcessspectrashowthattheanionsinteractwithmethanolmoleculesbyweakhydrogenbondingandthestrengthofthehydrogenbondsdecreaseaccordingtotheorder：CH3OH-CH30H>Cl__CH3OH>N0；一

6、CHH>C102一CH30H．Additionally，nointeractionsbetweencationsandmethanolmoleculesareapparent，asdeterminedafteranalysisofthisregion．IntheC——Ostretchingregion，theexcessRamanspectrashowtheinteractionsbetweenanions(cationsandmethanolmolecules．TheC—Ostretchingvibr

7、ationfrequenciesofmethanolthatinteractwiththeanionsandcationsincreaseaccordingtotheorder：CH3一OH(anions)

8、ationnumbersinthefirstsolvationshelloftheionsTheRamanspectrashowthattheionsdonotaffectthemicrostructureofliquidmethanolbeyondthefirstsolvationshellatthisconcentrationf一0．005)．KeyWords：Ramanspectrum；Anion；Cation；Methanol；Fi