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.
Full-dimensional (12D) variational vibrational states of CH$_4\cdot$F$^-$: interplay of anharmonicity and tunneling
甲烷分子和氟阴离子的复合物代表了一个12维（12 D），四阱振动问题，具有多个大振幅运动，多年来一直挑战着量子动力学界。目前的工作报告振动带的起源和隧道分裂得到的全维变分振动计算使用GENIUSH程序和SNORAK正交计划。收敛的12维振动带起源和隧道分裂证实了早期全维和降维研究的互补方面：（1）隧道分裂小于0.02 cm $^{-1}$ ;（2）单井处理是不够的（也许零点振动除外），这是由于井上的显著非谐性造成的;因此，（3）全维处理似乎是必要的。目前的计算扩展到更高的能量范围比早期的工作，表明隧道分裂增加后，振动激发的复杂的，并表示不可忽略的“重原子”隧穿。
Derivation of instanton rate theory from first principles
瞬子速率理论被用来研究包括低温化学反应在内的各种系统中的隧穿事件。尽管有许多成功的应用，但该方法从未从第一原理获得，而是依赖于“ImF”前提。本文从量子散射理论[W. H.米勒，S。D. Schwartz和J. W. Tromp，J.Chem.Phys.79，4889（1983）]使用半经典格林函数形式主义。这证明了瞬子的方法，并提供了一个路线，以获得其他过程的速率。
Schrödinger equation with Pauli-Fierz Hamiltonian and double well potential as model of vibrationally enhanced tunneling for proton transfer in hydrogen bond
Identification of the Atomic Scale Structures of the Gold-Thiol Interfaces of Molecular Nanowires by Inelastic Tunneling Spectroscopy
我们从理论上研究了金-硫醇界面上的键合几何形状对桥接金电极的丙二硫醇（PDT）分子的非弹性隧穿光谱的影响，并表明非弹性隧穿光谱与理论相结合可以用来确定这些键合几何形状的实验。借助密度泛函理论，我们计算了由一个或两个PDT分子连接两个金纳米团簇组成的扩展分子的弛豫几何构型和振动模式。我们制定了一个微扰理论的非弹性隧穿分子桥接金属接触的弹性传输振幅，并使用此理论计算的非弹性隧穿光谱的金-PDT-金扩展分子。我们认为PDT分子与反式和gauche构象绑定到顶部，桥和空心键合位点的金簇。将我们的结果与Hihath等人的实验数据进行比较[Nano Lett. 8，1673（2008）]中，我们确定实验中最频繁实现的构象为与两个电极顶部结合的反式分子的构象。我们发现从42 meV的振动模式的46 meV的模式在实验中观察到的切换是由于过渡的反式分子从混合顶桥纯顶位键合的几何形状。我们的研究结果还表明，gauche分子构象和空心网站键并没有显着的实验非弹性隧穿谱的贡献。对于对PDT分子并联连接的金电极，我们发现总弹性电导接近两倍的单分子桥接的接触，具有类似的键合构象和小分裂的振动模式的能量的模式，是最敏感的分子电极键合几何形状。
