Quantum Dynamics of Coupled Large Amplitude Intermolecular Motions in Hydrogen-Bonded and Rare-Gas Heteroclusters

纽约大学的Zlatko Bacic教授得到了 理论和计算化学计划。 该项目旨在 提供大振幅的精确量子力学描述 分子间振动和分子间势能 两个氢键团簇，苯-（H2O）n和（H2O）n的表面， 以及氩团簇中H_2O的紫外光解离， 其他稀有气体矩阵。 一个有效的量子6D方法将是 开发了用于计算激发的6D分子间振动 一个大的芳香族化合物之间的一个广泛的类复合物的本征态 分子（例如，苯、萘）和小的多原子分子 例如H2O、NH3。 振动平均结构和量子 较大的苯-水团簇的隧穿动力学将被探索 使用刚体量子蒙特卡罗方法。 一套办法以供 扭转能级的n维量子计算， 小团簇（H_2O）_n（n=3-6）的远红外光谱 并扩展到簇的其他分子间振动。 约束 水和氘代水团簇的状态计算将 描述它们的扭转振动动力学，量子数 分配和振动平均旋转常数。 Ar_nH_2O（n=1- 12，54）团簇和稀有气体中H_2O的光解 矩阵将进行研究，以获得了解的机制， 其中溶剂改变了 多原子溶质（H2O），相对于孤立的气相 分子。 光解离动力学将使用 经典的轨迹，而初始条件将产生 从氩-水团簇的量子6D分子间本征态 处于基态电子态。 定量了解的性质，和过程， 水和水溶液最终取决于详细的知识 水-水，水-溶质，溶质-溶质相互作用的结果。 的 Bacic教授对苯-水的量子计算和简单的 水团簇是测定它们分子间 高分辨率光谱数据的势能面。 这些 多维势应允许表征分子 液态水和水-苯的水平，系统是基本的 的实际重要性。 此外，更深入的了解将是 复杂氢键的复杂动力学性质 网络，它塑造了凝聚相的性质， 重要的大分子。

Professor Zlatko Bacic of New York University is being supported by theTheoretical and Computational Chemistry program. The project aims to provide an accurate quantum mechanical description of the large amplitude intermolecular vibrations and the intermolecular potential energy surfaces of two hydrogen-bonded clusters, benzene-(H2O)n and (H2O)n, as well as the ultraviolet photodissociation of H2O in argon clusters and other rare gas matrices. An efficient quantum 6D method will be developed for the calculation of excited 6D intermolecular vibrational eigenstates of a broad class of complexes between a large aromatic molecule (e.g., benzene, naphthalene) and a small polyatomic molecule such as H2O, NH3. Vibrationally averaged structures and quantum tunneling dynamics of larger benzene-water clusters will be explored using a rigid-body quantum Monte Carlo method. A methodology for n-dimensional quantum calculation of the torsional energy levels and far-infrared spectra of small (H2O)n (n=3-6) clusters will be developed and extended to other intermolecular vibrations of the clusters. Bound state calculations of water and deuterated water clusters will characterize their torsional vibrational dynamics, quantum number assignments, and vibrationally averaged rotational constants. Photodissociation of H2O in Ar_nH2O (n=1-12,54) clusters and rare-gas matrices will be studied to gain an understanding of the mechanisms by which the solvent modifies the photo-fragmentation dynamics of a polyatomic solute (H2O), relative to that of the isolated gas-phase molecule. The photodissociation dynamics will be simulated using classical trajectories, whereas the initial conditions will be generated from the quantum 6D intermolecular eigenstates of the argon-water cluster in the ground electronic state. A quantitative understanding of the properties of, and processes in, water and aqueous solutions ultimately depends on the detailed knowledge of the water-water, water-solute, and solute-solute interactions. The quantum calculations of Professor Bacic for benzene-water and simple water clusters are a tool for the determination of their intermolecular potential energy surfaces from high-resolution spectroscopic data. These multidimensional potentials should allow characterization on a molecular level of liquid water and water-benzene, systems which are of fundamental and practical importance. In addition, a deeper understanding will be gained of the intricate dynamical properties of complex hydrogen bonding networks, which shape the properties of condensed phases and biologically important macromolecules.