Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
J Mol Model. 2013 Apr;19(4):1937-42. doi: 10.1007/s00894-013-1763-6. Epub 2013 Jan 24.
The study reported herein addressed the structure, adsorption energy and normal modes of zwitterion L-cysteine (Z-cys) adsorbed on the Au₂₀ cluster by using density functional theory (DFT). It was found that four Z-cys are bound to the Au₂₀ apexes preferentially through S atoms. Regarding normal modes, after adsorption of four Z-cys molecules, a more intense infrared (IR) peak is maintained around 1,631.4 cm(-1) corresponding with a C=O stretching mode, but its intensity is enhanced approximately six times. The enhancement in the intensity of modes between 0 to 300 cm(-1) is around 4.5 to 5.0 times for normal modes that involve O-C=O and C-S bending modes. Other two normal modes in the range from 300 to 3,500 cm(-1) show enhancements of 6.0 and 7.4 times. In general, four peaks show major intensities and they are related with normal modes of carboxyl and NH₃ groups of Z-cys.
本文采用密度泛函理论（DFT）研究了两性离子 L-半胱氨酸（Z-cys）在 Au₂₀ 团簇上的吸附结构、吸附能和正则振动模式。研究发现，四个 Z-cys 优先通过 S 原子与 Au₂₀ 顶点结合。关于正则振动模式，在吸附四个 Z-cys 分子后，与 C=O 伸缩模式对应的大约 1631.4cm(-1) 附近仍保持较强的红外（IR）峰，但强度增强了约六倍。涉及 O-C=O 和 C-S 弯曲模式的 0 到 300cm(-1) 之间的模式的强度增强约为 4.5 到 5.0 倍。300 到 3500cm(-1) 范围内的其他两个正则振动模式的增强倍数为 6.0 和 7.4 倍。一般来说，四个峰显示出主要的强度，它们与 Z-cys 的羧基和 NH₃ 基团的正则振动模式有关。
