从拉曼光谱看液态甲醇的微观结构。

The microscopic structure of liquid methanol from Raman spectroscopy.

机构信息

Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.

出版信息

J Phys Chem B. 2010 Mar 18;114(10):3567-73. doi: 10.1021/jp9121968.

DOI:10.1021/jp9121968

PMID:20178325

Abstract

The microscopic structure of liquid methanol has been systematically investigated with Raman spectroscopy in a temperature range of 15-55 degrees C. The unbonded free -OH stretching vibrational band has been observed at approximately 3660 cm(-1) in pure liquid. With the aid of depolarization measurements and theoretical calculations, four featured spectral components have been unambiguously identified and assigned to four well-defined vibrational modes of clusters in chain or ring forms. Furthermore, the cluster size distribution and its temperature dependence have been derived from the spectral fittings for the first time, which lead to the conclusion that the trimer, tetramer, and pentamer are the dominant clusters in liquid methanol, taking up more than 50% of total clusters.

摘要

已使用拉曼光谱法在 15-55°C 的温度范围内对液态甲醇的微观结构进行了系统研究。在纯液态甲醇中，观察到非键合游离 -OH 伸缩振动带约为 3660cm(-1)。借助退偏测量和理论计算，已明确识别并分配了四个特征谱分量，它们对应于链状或环状形式的簇的四个明确的振动模式。此外，首次通过光谱拟合推导出了簇大小分布及其与温度的关系，这得出了以下结论：在液态甲醇中，三聚体、四聚体和五聚体是主要的簇，占总簇的 50%以上。