Molecular and Atomic Spectroscopy Laboratory, Department of Chemistry, Faculty of Sciences, University of Playa Ancha, Valparaiso, Chile.
Spectrochim Acta A Mol Biomol Spectrosc. 2013 Oct;114:120-8. doi: 10.1016/j.saa.2013.05.012. Epub 2013 May 28.
Infrared, Raman and SERS spectra of O,S-Dimethyl phosphoramidothioate, metamidophos, MAP, have been recorded. Density Functional Theory, DFT, with the B3LYP functional was used for the optimization of the ground state geometry and simulation of the infrared and Raman spectra of this molecule. Calculated geometrical parameters fit very well with the experimental ones. Combining the recorded data, the DFT results and a Normal Coordinate Analysis based on a scaled quantum mechanical (SQM) force field approach, a complete vibrational assignment was made for the first time. The comparison of SERS spectra obtained by using colloidal silver nanoparticles, with the corresponding Raman spectrum reveals enhancement and shifts in bands as well as information about the orientation of MAP on the nm-sized metal structures and the importance of the S atom on the SERS effect. DFT modelling of the SERS effect and Molecular Electrostatic Potentials (MEP) confirms the experimental information.
记录了 O，S-二甲基磷酰胺硫代酯、甲胺磷、MAP 的红外、拉曼和 SERS 光谱。采用密度泛函理论（DFT），B3LYP 函数对基态几何结构进行了优化，并对该分子的红外和拉曼光谱进行了模拟。计算得到的几何参数与实验值非常吻合。结合记录的数据、DFT 结果和基于标度量子力学（SQM）力场方法的正则坐标分析，首次对其进行了完整的振动分配。使用胶体银纳米粒子获得的 SERS 光谱与相应的拉曼光谱的比较，揭示了谱带的增强和位移，以及关于 MAP 在纳米级金属结构上的取向以及 S 原子在 SERS 效应中的重要性的信息。SERS 效应的 DFT 建模和分子静电势（MEP）证实了实验信息。
