噻吩在M（111）（M=Pd，Pt，Au）表面的吸附

摘要

采用密度泛函理论(DFT),选取DMol3程序模块,对噻吩在M(111)(M=Pd, Pt, Au)表面上的吸附行为进行了探讨。通过对噻吩在不同底物金属上的吸附能、吸附构型、Mul iken电荷布居、差分电荷密度以及态密度的分析发现,噻吩在Pd(111)面上的吸附能最大, Pt(111)面次之, Au(111)面最小。吸附后,噻吩在Au(111)面上的构型几乎保持不变,最终通过S端倾斜吸附于top位；噻吩在Pd(111)及Pt(111)面上发生了折叠与变形,环中氢原子向上翘起,最终通过环平面平行吸附于hol ow位。此外,噻吩环吸附后芳香性遭到了破坏,环中碳原子发生sp3杂化,同时电子逐渐由噻吩向M(111)面发生转移, M(111)面上的部分电子也反馈给了噻吩环中的空轨道,这种协同作用最终导致了噻吩分子稳定吸附于M(111)面。%The adsorption of thiophene on Pd(111), Pt(111), and Au(111) surfaces was investigated by periodic density functional theory (DFT) calculations at the GGA/PW91 level. The results showed that the adsorption energies of thiophene on the different surfaces fol owing the order Pd(111)>Pt(111)>Au(111). The adsorption structure on the Au(111) surface showed almost no change, and the most stable adsorption structure was tilted adsorption on the top site through the S atom of thiophene. For the Pd(111) and Pt(111) surfaces, the most stable adsorption structure was paral el adsorption to the hol ow site through the ring plane of thiophene. After adsorption, the H atom of thiophene moved upward and the structure of thiophene was distorted and folded. The aromaticity of thiophene was disrupted and the C atoms were characteristic of sp3 hybridization. Furthermore, the electrons of the M(111) surfaces and thiophene were redistributed after adsorption. The electron transfer from thiophene to the M(111) surfaces was in the order Pd(111)>Pt(111)>Au(111). The electrons of the M(111) surfaces were also back-denoted to the empty orbitals of the thiophene molecule. These processes eventual y lead to the adsorption of thiophene on the M(111) surfaces.