引用本文:
【打印本页】   【HTML】   【下载PDF全文】   View/Add Comment  【EndNote】   【RefMan】   【BibTex】
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 1902次   下载 1060 本文二维码信息
码上扫一扫!
分享到: 微信 更多
Absolute Orientation of Molecules with Competing Hydrophilic Head Groups at the Air/Water Interface Probed with Sum Frequency Generation Vibrational Spectroscopy
Feng Wang,Zhi Huang,Zhi-feng Cui *,Hong-fei Wang *
Author NameAffiliationE-mail
Feng Wang Department of Physics, Anhui Normal University, Wuhu 241000, China  
Zhi Huang Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China  
Zhi-feng Cui * Department of Physics, Anhui Normal University, Wuhu 241000, China  
Hong-fei Wang * Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, ChinaDepartment of Physics, Anhui Normal University, Wuhu 241000, China hongfei@iccas.ac.cn 
Abstract:
The constructive or destructive spectral interference between the molecular groups oriented up and down at the interface in the sum-frequency generation (SFG) spectra provides a direct measurement of the absolute orientation of these molecular groups. This simple approach can be employed to interrogate absolute molecular orientations other than using the complex absolute phase measurement in the SFG studies. We used the -CN group in the p-cyanophenol (PCP) molecule as the internal phase standard, and we measured the phases of the SFG fields of the ?CN groups in the 3,5-dimethyl-4-hydroxy-benzonitrile (35DMHBN) and 2,6-dimethyl-4-hydroxy-benzonitrile (26DMHBN) at the air/water interface by measuring the SFG spectra of the aqueous surfaces of the mixtures of the PCP, 35DMHBN, and 26DMHBN solutions. The results showed that the 35DMHBN had its -CN group pointing into the aqueous phase; while the 26DMHBN, similar to the PCP, had its -CN group pointing away from the aqueous phase. The tilt angles of the -CN group for both the 35DMHBN and 26DMHBN molecules at the air/water interface were around 25o-45o from the interface normal. These results provided insights on the understanding of the detailed balance of the competing factors, such as solvation of the polar head groups, hydrogen bonding and hydrophobic effects, etc., on influencing the absolute molecular orientation at the air/water interface.
Key words:  Sum frequency generation vibrational spectroscopy, Air/water interface,Molecule orientation, p-cyanophenol
FundProject:
Absolute Orientation of Molecules with Competing Hydrophilic Head Groups at the Air/Water Interface Probed with Sum Frequency Generation Vibrational Spectroscopy
汪凤,黄芝,崔执凤 *,王鸿飞 *
摘要:
和频振动光谱(SFG-VS)研究中由基团在界面上取向所引起的光谱增强或相消的干涉现象为研究分子在界面上的绝对取向提供了一种直接的测量方法. 这一方法比SFG实验中复杂的相位测量方法更为直接和简单可行. 以在空气/水界面取向已知的对羟基苯腈(PCP)分子的氰基(-CN)基团为相位参考来获得3,5-二甲基对羟基苯腈(35DMHBN)和2,6-二甲基对羟基苯腈(26DMHBN)分子在空气/水界面的取向信息. 通过对这三种分子的水溶液和它们两两混合溶液界面上-CN基团和频振动光谱强度的比较,发现在空气/水界面的3
关键词:  和频振动光谱,空气/水界面,分子取向,对羟基苯腈
DOI:10.1088/1674-0068/22/02/197-203
分类号: