用低温光谱方法揭示氢键的结构特征

本文提出了一种利用红外光谱方法揭示晶态物质中分子的氢键结构的新方法。用ＫＢｒ压片和氟油研磨法制备于红光谱测量的样品。测得的光谱有时基本相同，有时同明显的差别。对此现象一直没有一个十分满意的解释。我们用低温红外光谱法证明压力诱导晶格中氢键网络的微细变化是造成不同产法测得的光谱不同的原因。具有平面氢键结构的晶体不能有效地的御加于样品上的应力，易一城较低的外力作用下发生结构畸变，因此，用ＫＢｒ压片和氟油

Orientation of H-Bonds Revealed by Cryogenic FTIR Spectroscopy

We propose a new way to reveal structural arrangement of hydrogen bond network using FTIR spectroscopy.When KBr pellet and fluorolube mull methods are used to prepare samples for IR measurements,the resultant spectra sometimes show significant differences,sometimes not.The reason is unknown.We use cryogenic FTIR spectra to prove pressure effect accounts for spectral variation in different sampling process.The sensitivity of the FTIR spectra to external pressure is related to the three dimensional arrangement of hydrogen bonding network in the sample.When hydrogen bonds are in one plane,they can not resist external pressure applied perpendicular to that plane.Consequently,large differences appear between the spectra obtained using KBr pellet and fluorolube mull methods.On the other hand,when hydrogen bonds orientate toward various directions,the hydrogen bonding system can resist pressure from any directions.Thus,the FTIR spectra exhibit little variation using different sampling methods.We propose that the spectral variation obtained using above methods is a criterion to judge whether the hydrogen bonds orientate toward various directions in three dimensional space or not.