反式乙烯基联吡啶表面增强拉曼光谱的密度泛函理论研究

反式乙烯基联吡啶具有极好的拉曼散射信号,经常用做探针分子.利用密度泛函理论(DFT)理论,采用BP86,BPw91和B3LYP等方法,Ag原子使用赝式基组,H,C,N等原子使用6-31+ +G(d,p)基组,计算了反式乙烯基联吡啶与银配合物(t-BPE-Ag)的Raman光谱,并且利用势能分布(PED)计算结果对t-BPE分子Raman光谱和SERS谱进行了详细的归属,DFT理论得到结果说明根据DFT理论计算t-BPE-Ag配合物得到的Raman光谱与实验SERS谱基本一致,并且键连Ag原子越多,与实验值会更接近,t-BPE-Ag配合物HOMO与LUMO的能级差估计在449～912 nm范围内.

Density functional theory calculation of SERS spectra of trans-1,2-bis(4-pyridyl)-ethylene on silver

It has been found that trans-1, 2-bis(4-pyridyl)-ethylene has the best SERS signal and can be employed as a kind of self-assembly ? Im for the exploration of the SERS-active on the silver foil substrate. The shifts in the experiment surface enhanced Raman scattering of trans-1,2-bis(4-pyridyl)-ethylene were simulated by density functional theory calculation with the BP86, BPw91, B3LYP method. The basis set of 6-31++G(d,p) and Lan12dz was used by H, C, N atoms and Ag atom for the t-BPE-Ag complex. The Raman spectra and surface enhanced Raman scattering of trans-1, 2-bis (4-pyridyl)-ethylene were assigned by the calculated results of potential energy distribution The density functional theory calculated results explain that the angles between pyridyl rings for t-BPE-Ag complex holding 0o. Thus, the calculated Raman spectra of trans-1, 2-bis(4-pyridyl)-ethylene and Ag complex accord with observed SERS results of t-BPE. The energy level space between the high occupied molecular orbital and lowest unoccupied molecular orbital is estimated to arise between 415 and 912 nm for trans-1,2-bis(4-pyridyl)-ethylene and Ag complex.