Quantum and classical vibrational relaxation dynamics of N‐methylacetamide on ab initio potential energy surfaces
Quantum and classical vibrational relaxation dynamics of N‐methylacetamide on ab initio potential energy surfaces
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DOI：
10.1002/qua.22061
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发表时间：
2008-07
影响因子：
2.2
通讯作者：
H. Fujisaki;K. Yagi;K. Hirao;J. Straub;G. Stock
中科院分区：
文献类型：
--
作者：
H. Fujisaki;K. Yagi;K. Hirao;J. Straub;G. Stock
利用DFT/B3LYP和MP2水平上的广泛量子化学计算，构建了分离的n -甲基乙酰胺的四次力场。考虑了24个振动自由度，采用该模型对酰胺I模式的振动能弛豫进行了数值精确的振动组态相互作用计算。研究发现，能量传递途径可能敏感地依赖于理论描述的细节。此外，利用精确参考计算研究了(i)准经典轨迹方法、（ii）随时间变化的二阶摄动理论和（iii）频率波动的瞬时正态模态描述的适用性和准确性。在此基础上，讨论了几种描述生物分子系统振动能量弛豫的策略。©2009 Wiley期刊公司量子力学学报，2009,31 (2):557 - 557
Employing extensive quantum-chemical calculations at the DFT/B3LYP and MP2 level, quartic force fields of isolated N-methylacetamide are constructed. Taking into account 24 vibrational degrees of freedom, the model is employed to perform numerically exact vibrational configuration interaction calculations of the vibrational energy relaxation of the amide I mode. It is found that the energy transfer pathways may sensitively depend on details of the theoretical description. Moreover, the exact reference calculations were used to study the applicability and accuracy of (i) the quasiclassical trajectory method, (ii) time-dependent second-order perturbation theory, and (iii) the instantaneous normal mode description of frequency fluctuations. Based on the results, several strategies to describe vibrational energy relaxation in biomolecular systems are discussed. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem 109: 2047-2057, 2009