Atomic and Molecular Doped Quantum Clusters

理论和计算化学项目正在支持加州大学伯克利分校的B.Whaley教授。这项研究将在未来三年内进行，将是对氦和氢量子团簇中的外来物种正在进行的理论研究的继续。这个研究项目有两个方面的设计。首先，当核离域和交换效应很重要时，建立处理复杂量子系统的结构、动力学和光谱的一般方法。该方法基于零温度和有限温度的量子蒙特卡罗方法，已被证明是分析量子团簇性质的有力工具。这里一个重要的算法发展是计算虚时间关联函数，它允许直接计算掺杂光谱。第二个目标是回答一些关于探测分子与其量子环境相互作用的公开问题，这些问题是最近关于掺杂量子团簇的实验提出的。因此，在这个资助周期的申请中，Whaley教授将重点研究这些星团的光谱。这包括掺杂分子的红外光谱，纯和原子掺杂量子团簇中的电子光谱和电子能量转移的性质。氦和氢的量子团簇具有不寻常的低温行为，这是化学界和物理界都感兴趣的。虽然它们在概念上很重要，因为它们为研究强量子系统中的有限尺寸效应提供了独特的机会，但它们作为软量子矩阵也有重要的实际应用，可以用来研究弱束缚系统的光谱和低温下的化学反应。这种量子微环境的用途最近通过在氦液滴中产生小的金属团簇而戏剧性地得到证明。这为研究金属颗粒的反应性开辟了一条新的受控途径。这一理论和计算研究的目的是发展对解释这种掺杂量子团簇的光谱特征所必需的理解，并为利用它们来控制新型超冷纳米尺度量子矩阵中的基本反应动力学提供预测能力。

The Theoretical and Computational Chemistry program is supporting Prof. B.Whaley at the University of California, Berkeley. The research, to be carried out over the next three years will be a a continuation of ongoing theoretical studies of foreign species in quantum clusters of helium and hydrogen. This research program has a two-fold design. First, to establish general methods of dealing with structure, dynamics and spectroscopy of complex quantum systems when nuclear delocalization and exchange effects are important. The approach is based on Quantum Monte Carlo methods, both zero and finite temperature, which have been shown to be powerful tools for analyzing the properties of quantum clusters. A significant algorithmic development here is the calculation of imaginary time correlation functions, which allows the calculation of dopant spectra directly. The second goal is to answer some open questions about the interaction of probe molecules with their quantum environment which have been raised by recent experiments on doped quantum clusters. Thus in the applications during this grant cycle, Prof Whaley will focus on the study of the spectroscopy of these clusters. This includes infra-red spectra of dopant molecules, electronic spectra and the nature of electronic energy transfer in pure and atomic-doped quantumclusters. Quantum clusters of helium and hydrogen possess unusual low temperature behavior which is of interest to both chemistry and physics communities. While conceptually of importance because of the unique opportunity they present for study of finite size effects in strongly quantum systems, theyalso have significant practical use as gentle quantum matrices which may be utilized to study spectroscopy of weakly bound systems and chemical reactions at low temperatures. The utility of this quantum micro-environment has recently been dramatically demonstrated with the production of small metal clusters inside a helium droplet. This opens a new controlled route to study of the reactivity of metal particles. The aim of this theoretical and computational investigation is to develop the understanding necessary to interpret spectral signatures of such doped quantum clusters, and to provide predictive power for using them to control elementary reaction dynamics in a novel ultra-cold nanoscale quantum matrix.