Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge, CB2 3RA, UK.
Phys Chem Chem Phys. 2010;12(20):5329-40. doi: 10.1039/b926536h.
The phonon modes of crystalline benzoic acid have been investigated using terahertz time-domain spectroscopy, rigid molecule atom-atom model potential and plane-wave density functional theory lattice dynamics calculations. The simulation results show good agreement with the measured terahertz spectra and an assignment of the terahertz absorption features of benzoic acid is made with the help of both computational methods. Focussing on the strongest interactions in the crystal, we describe each vibration in terms of distortions of the benzoic acid hydrogen bonded dimers that are present in the crystal structure. The terahertz spectrum is also shown to be highly sensitive to the location of the carboxylic acid hydrogen atoms in the cyclic hydrogen-bonded dimers and we have systematically explored the influence of the observed disorder in the hydrogen atom positions on the lattice dynamics.
利用太赫兹时域光谱、刚性分子原子-原子模型势能和平面波密度泛函理论晶格动力学计算研究了晶体苯甲酸的声子模式。模拟结果与测量的太赫兹光谱吻合较好，并借助这两种计算方法对苯甲酸的太赫兹吸收特征进行了归属。本文重点研究了晶体中的最强相互作用，根据晶体结构中存在的苯甲酸氢键二聚体的扭曲，描述了每个振动。太赫兹光谱也对环状氢键二聚体中羧酸氢原子的位置高度敏感，我们系统地研究了观察到的氢原子位置无序对晶格动力学的影响。
