[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.