丙氨酸晶体太赫兹振动光谱的实验和理论研究  

Experimental and Theoretical Investigations on the Terahertz Vibrational Spectroscopy of Alanine Crystal

作　　者：王果[1] 王卫宁[2] 

机构地区：[1]首都师范大学化学系,北京100048 [2]首都师范大学物理系,北京市太赫兹波谱与成像重点实验室,教育部太赫兹光电子重点实验室,北京100048

出　　处：《物理化学学报》2012年第7期1579-1585,共7页Acta Physico-Chimica Sinica

基　　金：国家重点基础研究发展规划项目(973)(2007CB310408)资助~~

摘　　要：利用太赫兹时域光谱和低频拉曼光谱仪研究了丙氨酸晶体在0.2-2.6THz范围内的太赫兹吸收和拉曼散射光谱.研究表明:在该低频范围有四个振动模式,其中两个只具有拉曼活性,其余两个同时具有红外和拉曼活性.基于B3LYP杂化密度泛函的自洽场晶体轨道法对丙氨酸周期性结构进行了理论研究和光谱计算.通过比较实验和理论结果,指认了实验光谱特征峰所属的不可约表示.通过理论计算得到的图形,得出在此低频范围的振动模式主要包含分子间氢键的扭转和摇摆运动.The terahertz absorption and Raman scattering spectra of an alanine crystal in the range of 0.2-2.6 THz were obtained using terahertz time-domain spectroscopy and low-frequency Raman spectroscopy. The results indicated that there were four vibrational modes in this low-frequency region. Two modes were Raman active whereas the other two were both infrared and Raman active. A theoretical investigation on the periodic structure of alanine was performed using a self-consistent field crystal orbital method based on the B3LYP hybrid density functional. By comparing the experimental and theoretical results, irreducible representations were assigned to the corresponding peaks in the spectra. It was indicated that the vibrational modes in this low-frequency region were mainly torsion or rocking modes involving inter-molecular hydrogen bonds which have been described using schematic representations.

关 键 词：丙氨酸晶体 太赫兹吸收光谱 太赫兹拉曼光谱 氢键 密度泛函理论 

分 类 号：O73[理学—晶体学]