Perturbation Approach for Computing Infrared Spectra of the Local Mode of Probe Molecules.
Perturbation Approach for Computing Infrared Spectra of the Local Mode of Probe Molecules.
复制标题
计算探针分子局域模式红外光谱的微扰方法
DOI：
10.1021/acs.jctc.6b00733
复制
发表时间：
2017-01-10
影响因子：
5.5
通讯作者：
Li H
中科院分区：
文献类型：
--
作者：
Xue RJ;Grofe A;Yin H;Qu Z;Gao J;Li H
位点特异性探针分子的线性和二维红外 (IR) 光谱提供了在分子水平上了解凝聚相和生物系统中的局部氢键网络、构象动力学和长程静电相互作用的机会。计算中的一个挑战是确定与时间相关的振动频率，该频率明确地包含振动运动的核量子效应和势能表面的电子结构表示。在本文中，描述了一种核量子振动扰动（QVP）方法，用于在分子动力学模拟中有效确定发色团的瞬时振动频率。计算效率是通过使用（a）振动波函数的离散变量表示，（b）用于评估由于溶剂动态波动引起的振动能量变化的微扰理论，以及（c）系统的组合 QM/MM 潜力来实现的。研究发现，一阶扰动足够准确，使得能够在分子动力学中即时获得与时间相关的振动频率。 QVP 方法在 HCl-水簇中的 H-Cl 伸缩频率和水溶液中丙酮的羰基伸缩振动的模式特定线性和 2D-IR 光谱中得到说明。为了进一步降低计算成本，提出了一种混合策略，结果发现计算的振动谱峰位置和线形与实验结果一致。此外，研究发现H-Cl伸缩模式下非简谐性显着，氢键相互作用进一步增强了非简谐效应。目前的 QVP 方法补充了其他计算方法，包括基于路径积分的分子动力学，并且代表了对基于静电的光谱映射程序的重大改进。
Linear and two-dimensional infrared (IR) spectroscopy of site-specific probe molecules provides an opportunity to gain a molecular-level understanding of the local hydrogen-bonding network, conformational dynamics, and long-range electrostatic interactions in condensed-phase and biological systems. A challenge in computation is to determine the time-dependent vibrational frequencies that incorporate explicitly both nuclear quantum effects of vibrational motions and an electronic structural representation of the potential energy surface. In this paper, a nuclear quantum vibrational perturbation (QVP) method is described for efficiently determining the instantaneous vibrational frequency of a chromophore in molecular dynamics simulations. Computational efficiency is achieved through the use of (a) discrete variable representation of the vibrational wave functions, (b) a perturbation theory to evaluate the vibrational energy shifts due to solvent dynamic fluctuations, and (c) a combined QM/MM potential for the systems. It was found that first-order perturbation is sufficiently accurate, enabling time-dependent vibrational frequencies to be obtained on the fly in molecular dynamics. The QVP method is illustrated in the mode-specific linear and 2D-IR spectra of the H–Cl stretching frequency in the HCl–water clusters and the carbonyl stretching vibration of acetone in aqueous solution. To further reduce computational cost, a hybrid strategy was proposed, and it was found that the computed vibrational spectral peak position and line shape are in agreement with experimental results. In addition, it was found that anharmonicity is significant in the H–Cl stretching mode, and hydrogen-bonding interactions further enhance anharmonic effects. The present QVP method complements other computational approaches, including path integral-based molecular dynamics, and represents a major improvement over the electrostatics-based spectroscopic mapping procedures.
登录
查看更多内容
影响因子：
3.4
作者：
Bu, LT;Straub, JE
通讯作者：
Straub, JE
影响因子：
2.9
作者：
Bacelo, DE;Binning, RC;Ishikawa, Y
通讯作者：
Ishikawa, Y
影响因子：
3.3
作者：
Boese, A. Daniel;Forbert, Harald;Jansen, Georg
通讯作者：
Jansen, Georg
影响因子：
15
作者：
Culik, Robert M.;Jo, Hyunil;DeGrado, William F.;Gai, Feng
通讯作者：
Gai, Feng
影响因子：
4.4
作者：
Braams, Bastiaan J.;Manolopoulos, David E.
通讯作者：
Manolopoulos, David E.