从头算分子动力学模拟再探 N-甲基乙酰胺的红外光谱。

Infrared Spectroscopy of N-Methylacetamide Revisited by ab Initio Molecular Dynamics Simulations.

机构信息

Laboratoire de Modélisation des Systèmes Moléculaires Complexes, Université d'Evry val d'Essonne, Rue Père A. Jarland, 91025 Evry, France, Laboratoire de Physique Théorique des Liquides, Université Pierre et Marie Curie, Case Courrier 121, 4 place Jussieu, 75005 Paris, France, and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.

出版信息

J Chem Theory Comput. 2005 Sep;1(5):772-89. doi: 10.1021/ct050029z.

DOI:10.1021/ct050029z

PMID:26641894

Abstract

The density functional theory based molecular dynamics simulation method ("Car-Parrinello") was applied in a numerical study of the electronic properties, hydrogen bonding, and infrared spectroscopy of the trans and cis isomer of N-methylacetamide in aqueous solution. A detailed analysis of the electronic structure of the solvated molecules, in terms of localized Wannier functions and Born atomic charges, is presented. Two schemes for the computation of the solute infrared absorption spectrum are investigated: In the first method the spectrum is determined by Fourier transforming the time correlation function of the solute dipole as determined from the Wannier function analysis. The second method uses instead the molecular current-current correlation function computed from the Born charges and atomic velocities. The resulting spectral properties of trans- and cis-NMA are carefully compared to each other and to experimental results. We find that the two solvated isomers can be clearly distinguished by their infrared spectral profile in the 1000-2000 cm(-)(1) range.

摘要

基于密度泛函理论的分子动力学模拟方法（“Car-Parrinello”方法）被应用于对 N-甲基乙酰胺在水溶液中的顺式和反式异构体的电子性质、氢键和红外光谱的数值研究。本文详细分析了溶剂化分子的电子结构，包括局域化的 Wannier 函数和玻恩原子电荷。研究了两种计算溶质红外吸收光谱的方案：第一种方法是通过对从 Wannier 函数分析中确定的溶质偶极子的时间相关函数进行傅里叶变换来确定光谱。第二种方法则使用从玻恩电荷和原子速度计算得到的分子电流-电流相关函数。对反式和顺式-NMA 的所得光谱性质进行了仔细的比较，并与实验结果进行了比较。我们发现，通过在 1000-2000cm(-1)范围内的红外光谱谱型，可以清楚地区分这两种溶剂化异构体。