压力是一个重要的物理参量, 通过调节物质内部分子、 原子间距离和相互作用力, 可以引起物质结构和构象变化。 正醇是一种最简单的羟基代替烷基链末端氢原子的有机物, 通过氢键和烷基链之间的作用力结合在一起, 被称为氢键液体。 氢键的键能较小, 在外部压力作用下, 氢键容易被压缩而断裂或网络重排, 从而导致晶体结构和对称性的改变, 对材料的性能产生重要影响。 正戊醇是一种短链正醇, 结构虽然简单, 却可以作为烷基链结构有机物的典型代表。 然而, 高压下正戊醇的性质研究较少, 尤其压力作用下其构象变化和氢键研究尚未见报道, 因此正戊醇高压研究有待进一步深入。 拉曼光谱和红外光谱是高压研究中常用的谱学测量技术, 能够原位探测压力作用下分子内部基团变化, 是研究结构、 构象和氢键作用的有效手段。 基于此, 利用金刚石对顶砧装置(DAC), 结合拉曼光谱和红外光谱, 在0～12.0 GPa压力范围对正戊醇进行了高压研究。 实验结果分三部分讨论: （1）研究了压力作用下正戊醇的结构相变行为。 压力在3.2 GPa时, 拉曼特征峰变锐变窄, 同时有特征峰劈裂和新特征峰出现的现象, 说明在该压力点发生一次液固相转变。 （2）揭示了正戊醇在高压下的构象变化。 正戊醇存在两种构象: 反式构象和扭曲构象。 通过分析两种构象特征峰随压力的变化, 发现正戊醇发生液固相转变的过程伴随有构象变化, 液态时以扭曲构象为主, 固态时以反式构象为主。 （3）探究了高压对正戊醇氢键的影响。 羟基的特征峰随压力的增加发生红移, 说明在加压过程中氢键作用增强。 伴随液固相变, 羟基特征峰劈裂成多个峰, 形成新的氢键网络或团簇, 且随压力的增加氢键网络或团簇逐渐增大, 说明氢键对压力非常敏感, 且对正戊醇晶体结构的稳定起着促进作用。 该研究不仅为正戊醇生产应用提供重要的指导作用, 同时为其他同类或复杂分子体系的物理和化学特性研究提供参考。

Hydrostatic pressure is a very important physical parameter. Application of hydrostatic pressure to molecular systems can adjust the distances and forces of the molecules and atoms, which can result in new structure and conformation change. Normal alkanols H(CH2)nOH are among the simplest substituted organic matters, in which a single OH group replaces a hydrogen atom at the end of the aliphatic chain. Normal alcohols are held together by the interplay between the hydrogen bond and the alkyl chain, and are called hydrogen bonded liquids. Hydrogen bonds are far weaker, so application of hydrostatic pressure to hydrogen-bonded organic molecules can compress hydrogen bonds. Large modifications can be observed in hydrogen bonds, including breakage and rearrangement. The changes in hydrogen bonds can lead to variations of crystal structures and symmetry, which will affect the properties of materials. N-pentanol (C5H12O) is short chain alcohol. It is simple in structure, but it can be a typical representative of alkyl chain organic compounds. However, the properties researches on n-pentanol under high pressure are scarce, especially studies on the conformational changes and hydrogen bonds under pressure have not been reported. So it is necessary to investigate n-pentanol at higher pressure, which is helpful to probe more information. Raman and IR spectroscopy are common spectral measurement techniques in high pressure research. They are useful for observing and providing interesting insights into the changes of the molecule. They are crucial tools, in studying structures, conformations and hydrogen bonds. Thus, in this paper, hydrogen-bonding and phase transitions of n-pentanol (C5H12O) have been investigated under high pressure usingRaman and Infrared spectroscopy. The high pressure Raman and IR spectrum have been collected as a function of high pressure to 12.0 GPa by using the diamond anvil cell (DAC). The experiment results have been discussed in section 3. In the first part, the Raman spectrum of n-pentanol have been measured under high pressure. The Raman spectrum showed that the characteristic peaks become sharpened, characteristic peaks split and new modes appear at 3.2 GPa. These results indicated that n-pentanol might experience a liquid to solid transition at 3.2 GPa. In the second part, the influence of high pressure on conformational behavior of n-pentanol has been analyzed. N-pentanol has two characteristic conformers, including TTTt conformer and GTTt conformer. The changes of characteristic peaks with pressure have been studied. The data analysis showed that conformational change between trans and gauche is observed accompanied by the phase transitions. It was concluded that the gauche conformation is the main form in the liquid n-pentanol and the trans conformation in solid state. In the last part, the effect of high pressure on hydrogen-bond of n-pentanol has been investigated. The red shift of O—H stretching modes indicates that the H-bond is strengthened with increasing in pressure. The O—H stretching modes split into multiple peaks, which implied that new clusters and hydrogen bonding network of n-pentanol have formed. With the pressure increasing, the cluster structure of n-pentanol has become more stable and bigger. These results suggested that hydrogen bond is sensitive to pressure and plays an important role in promoting the stability of n-pentanol crystal structure. The high-pressure study on n-pentanol can provide a theoretical basis for the study of physical and chemical properties of similar or complex molecular systems.