Anharmonic vibrational spectroscopy of the glycine-water complex:: Calculations for ab initio, empirical, and hybrid quantum mechanics/molecular mechanics potentials
Anharmonic vibrational spectroscopy of the glycine-water complex:: Calculations for ab initio, empirical, and hybrid quantum mechanics/molecular mechanics potentials
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DOI：
10.1063/1.1379040
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发表时间：
2001-07-15
影响因子：
4.4
通讯作者：
Gerber, RB
中科院分区：
文献类型：
--
作者：
Chaban, GM;Gerber, RB
利用从头算（二阶Moller-Plesset摄动理论）、经验（OPLS-AA）和混合从头算/经验量子力学/分子力学（QM/MM）势，研究了甘氨酸和一个水分子之间的分子间氢键对振动谱的影响。采用相关校正振动自洽场法计算振动谱，该方法考虑了不同振型之间的非谐性和耦合。发现分子间氢键相互作用非常强，并在很大程度上影响甘氨酸和水分子的振动频率和红外强度。在实验研究中，预测的从头算非调和谱可用于识别与水配合物中的氨基酸。发现OPLS-AA电位不正确地描述了甘氨酸和水之间的氢键，并预测了错误的振动谱。然而，混合（QM/MM）技术可以用于计算更可靠的振动谱，与整个系统的完全从头算处理一致，只要包含氢键的区域是由从头算势描述的。(C) 2001年美国物理研究所。
Effects of intermolecular hydrogen bonding between glycine and one water molecule on the vibrational spectrum are investigated, using ab initio (at the level of second order Moller-Plesset perturbation theory), empirical (OPLS-AA), and mixed ab initio/empirical quantum mechanics/molecular mechanics (QM/MM) potentials. Vibrational spectroscopy is calculated using the correlation corrected vibrational self-consistent field method that accounts for anharmonicities and couplings between different vibrational normal modes. The intermolecular hydrogen bonding interactions are found to be very strong and to affect vibrational frequencies and infrared intensities of both the glycine and the water molecule to a very large extent. The predicted ab initio anharmonic spectra can be used to identify amino acids in complexes with water in experimental studies. The OPLS-AA potential is found to describe hydrogen bonding between glycine and water incorrectly, and to predict erroneous vibrational spectra. Hybrid (QM/MM) techniques can, however, be used to calculate more reliable vibrational spectra, in agreement with full ab initio treatment of the whole system, provided that the regions that contain hydrogen bonds are described by ab initio potentials. (C) 2001 American Institute of Physics.