论文标题
分子的振动隧穿光谱与非对称井：一种组合的振动构型相互作用和Instanton方法
Vibrational tunneling spectra of molecules with asymmetric wells: a combined vibrational configuration interaction and instanton approach
论文作者
论文摘要
使用振动自洽场（VSCF）和振动构型相互作用（VCI）方法以及半经典插入理论的组合方法被开发为研究分子的振动隧道频谱，并具有多个井的分子。该方法可以应用于计算具有任意井数的系统中的低洼振动状态，这不一定与对称操作相关。它特别适合于井被大型潜在障碍分离的系统，并且隧道分裂很小，因此确切的量子机械方法的计算成本过高。该方法的准确性在二维双孔模型系统和丙醛中测试，并将结果与精确的量子力学计算进行了比较。随后将该方法应用于非对称脱水的丙二醛，该醛在两个孔中具有非分级振动频率。该频谱以单孔VSFC/VCI计算为代价获得。不同井的状态之间的相互作用是以相对可忽略的计算成本进行半经典计算的。该方法特别适合水簇研究中的光谱的计算和分配。
A combined approach that uses the vibrational self-consistent field (VSCF) and vibrational configuration interaction (VCI) method together with the semiclassical instanton theory was developed to study vibrational tunneling spectra of molecules with multiple wells. The method can be applied to calculate low-lying vibrational states in the systems with arbitrary number of wells, which are not necessarily related by a symmetry operation. It is particularly suited to systems in which the wells are separated by large potential barriers and tunneling splittings are small, so that the exact quantum-mechanical methods come at a prohibitive computational cost. The accuracy of the method was tested on a two-dimensional double-well model system and on malonaldehyde, and the results were compared with the exact quantum-mechanical calculations. The method was subsequently applied to the asymmetrically deuterated malonaldehyde, which has non-degenerate vibrational frequencies in the two wells. The spectrum is obtained at a cost of single-well VSFC/VCI calculations. The interactions between states of different wells are computed semiclassically at a comparatively negligible computational cost. The method is particularly suited to the computation and assignment of spectra in the studies of water clusters.
