Ab initio molecular dynamics computation of the infrared spectrum of aqueous uracil
Ab initio molecular dynamics computation of the infrared spectrum of aqueous uracil
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DOI：
10.1021/jp034788u
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发表时间：
2003-09-25
影响因子：
3.3
通讯作者：
Sprik, M
中科院分区：
文献类型：
--
作者：
Gaigeot, MP;Sprik, M
通过对尿嘧啶水溶液的应用的详细说明，回顾并说明了用于计算凝聚分子系统中红外吸收光谱的从头算分子动力学方法的最新进展。与经典力场模拟类似，频谱是通过极化时间自相关函数的傅里叶变换获得的。简要概述了计算周期性超晶胞中电子极化的密度泛函方法，并讨论了量子校正的影响。模型系统在2000-1000 cm(-1)范围内获得的光谱图与实验吻合良好。与通过类似时间相关方法计算的低温真空光谱相比，我们发现真空中的窄酰胺弯曲带在溶液中分布在500 cm(-1)宽的区间内，并且高频端明显蓝移。 N1-H1 弯曲的频率增加最高。相比之下，C=O 伸缩带的红移和展宽的影响要小得多。
Recent progress in the development of ab initio molecular dynamics methods for the computation of infrared absorption spectra in condensed molecular systems is reviewed and illustrated by a detailed account of an application to aqueous uracil. Similar to classical force field simulations, the spectrum is obtained as the Fourier transform of the polarization time autocorrelation function. The density functional methodology for the computation of electronic polarization in periodic supercells is briefly outlined, and also the effect of quantum corrections is discussed. The spectral patterns obtained for the model system in the 2000-1000 cm(-1) domain are in good agreement with experiment. Comparing to the low-temperature vacuum spectrum computed by similar time-dependent methods, we found that the narrow amide bending band in a vacuum is spread out over a 500 cm(-1) wide interval in solution with a substantially blue-shifted high-frequency end. The highest increase in frequency was found for N1-H1 bending. The red shift and broadening of C=O stretching bands is, in comparison, a much smaller effect.