摘要
采用密度泛函理论(DFT)B3LYP方法,6-311G(d,p)(C,H,O)/LANL2DZ(Ag)基组,计算了黄曲霉素B2(AFB2)分子吸附在Ag2团簇的表面增强拉曼散射(SERS)光谱和预共振拉曼光谱,并与实验结果比较.结果显示:AFB2分子在基态Ag2团簇表面吸附时,增强因子最大达到102,对应吡喃(pyrane)环C=O伸缩振动,主要是由AFB2分子周围化学环境改变而引起的基态静极化率改变导致的化学增强.不同激发波长下的AFB2分子预共振拉曼光谱的增强强度不同:电荷转移态激发波长为1144和544 nm时拉曼信号增强了102倍,而选择电荷转移预共振波长432和410 nm作为入射光时,其拉曼信号增强了104倍,增强机理为银团簇和黄曲霉素分子之间的电荷转移共振增强.因此通过改变入射光波长,选择电荷转移共振激发波长,更有利于强致癌物AFB2分子的痕量检测.
The surface-enhanced Raman scattering （SERS） spectrum and pre-resonance Raman spectra of Aflatoxin B2 （AFB2） adsorbed on silver cluster were calculated by density functional theory （DFT） methods with the B3LYP/6-311G （d,p）（C, H, O）/LanL2DZ（Ag） basis set. The results show that the SERS enhancement factors were 10^2, and this belongs to the C=O stretching vibration of the pyrane ring because of the larger static polarizability of the complex. The pre-resonance Raman spectra of the AFB2-Ag2 complex were explored at 1144 and 544 nm, which corresponds to charge transfer excitation energy, and its enhancement factor was 10^2. The pre-resonance enhancement factor was 10^4 when incident light charge transfer pre-resonant wavelengths of 432 and 410 nm were selected. These come from a charge transfer resonance enhancement between the silver cluster and the AFB2 molecule. Therefore, changing the wavelength of the incident light is more conducive to the trace detection of the strong carcinogen AFB2.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2014年第10期1916-1922,共7页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(11174237)
国家重点基础研究发展计划(973)(2013CB328904)
四川省应用基础项目(2013JY0035)
中央高校基本科研业务费专项资金资助~~
关键词
黄曲霉素B2
表面增强拉曼散射光谱
预共振拉曼光谱
密度泛函理论
Aflatoxin B2
Surface-enhanced Raman scattering spectrum
Pre-resonant Ramanspectrum
Density functional theory
