Department of Physics, Banaras Hindu University, Varanasi, Uttar Pradesh , India.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Oct 15;77(3):559-65. doi: 10.1016/j.saa.2010.04.011. Epub 2010 Apr 22.
Raman spectra of acetonitrile (Acn) in different millimolar (mM) concentrations adsorbed on Ag nano-colloids were recorded in the region 2100-3300cm(-1). The nu(CN) and nu(C-H) modes show blue shifts of approximately 3 and approximately 1cm(-1), respectively, when the concentration of Acn in the mixture is increased from 2 to 8mM. The blue shift of nu(CN) and nu(C-H) modes is predominantly because of adsorption of Acn molecules on Ag nano-colloids. The wave number shift and variation of intensity of the nu(CN) and nu(C-H) bands have been discussed in terms of the adsorption geometry, which probably changes from flat-on configuration at lower concentration of Acn to an end-on configuration at higher concentration of Acn. The dephasing of nu(CN) oscillator becomes considerably slower at higher concentration of Acn. The adsorption of Acn molecules on the nano-colloids was simulated using the (B3LYP) method and the basis sets used for Acn molecules and Ag atoms were 6-311++G(d,p) and Lanl2dz, respectively.
记录了吸附在 Ag 纳米胶体上的不同毫摩尔（mM）浓度的乙腈（Acn）的拉曼光谱，波数范围为 2100-3300cm(-1)。当混合物中 Acn 的浓度从 2mM 增加到 8mM 时，nu(CN)和 nu(C-H)模式分别有约 3cm(-1)和约 1cm(-1)的蓝移。nu(CN)和 nu(C-H)模式的蓝移主要是由于 Acn 分子在 Ag 纳米胶体上的吸附。nu(CN)和 nu(C-H)带的波数位移和强度变化是根据吸附几何形状讨论的，其可能从 Acn 较低浓度时的平面构型变为 Acn 较高浓度时的端接构型。nu(CN)振荡器的退相在较高浓度的 Acn 时变得相当慢。使用（B3LYP）方法模拟了 Acn 分子在纳米胶体上的吸附，用于 Acn 分子和 Ag 原子的基组分别为 6-311++G(d,p)和 Lanl2dz。
