以量子化学计算作为起点,为最简单的糖类分子——乙醇醛开发了两套分子力学力场参数:基于肽类的力场和基于醛类的力场.分子动力学模拟结果表明,所开发的类醛力场参数能够较好地描述乙醇醛分子在水中的结构以及水分子在其周围的分布.通过瞬时简正模式分析,得到了3N-6个模式的瞬时振动频率和振动跃迁偶极矩等振动光谱参数的统计分布及其相关性.结合量子化学计算和分子动力学模拟对生物分子体系的多元振动光谱参数进行预测和评估,为从化学键水平出发模拟宽带飞秒二维红外相关光谱提供了一个新方法.
From quantum chemical computations,two sets of molecular mechanics force fields based on peptides and aldehydes were developed for the simplest sugar——glycolaldehyde. Molecular dynamics simulations demonstrated that the structure of glycolaldehyde and the solvent water distribution can be better described by aldehyde-like parameters. Probabilities of normal mode frequencies and dipole derivatives were obtained by instantaneous normal mode analysis. This is thus a new way to predict the parameters of femtosecond broadband two-dimensional infrared spectroscopy for biomolecules by combining quantum mechanics calculation and molecular dynamics simulation.