Theoretical Studies of Molecular Ions and Clusters

匹兹堡大学化学系的Kenneth D.Jordan教授得到了美国国家科学基金会理论和计算化学项目的资助，用于与分子体系的电子和几何结构相关的研究。他在这笔赠款下的工作主要有三个方面。第一个研究领域涉及中等大小星系团的热力学性质。这项工作涉及到精确的量子化学确定各种团簇几何结构的总相互作用能，然后模拟能量面上的运动动力学。第二个领域涉及对硅表面反应的研究。在这项工作中，有限团簇被用来模拟吸附在表面上和与表面一起的运动和反应。最后，正在进行研究，以验证和推广用于研究大分子和团簇的各种理论方法。理论电子结构方法已经确立，并经常应用于两个极端；一个极端是只由几个原子组成的小系统，另一个极端是结晶固体。这项赠款下的工作涉及正在为两个科学目的而研究的星系团的中间情况。第一个原因是考察处于两极之间的中间状态的物质的性质；这种状态特别重要，因为它具有与极端情况下的性质根本不同的性质。这项拨款下的工作正在帮助探索这些迷人的、潜在有用的星系团属性。第二个原因是用合适的团簇模型研究固体表面的性质。这种模型对阐明表面化学特别有用，因为它们使解释和预测分子中化学的理论能够应用于发生在凝聚态物质表面的过程。

Professor Kenneth D. Jordan at the Department of Chemistry, University of Pittsburgh, is supported by a grant from the Theoretical and Computational Chemistry Program at NSF for studies related to the electronic and geometric structure of molecular systems. His work under this grant is, primarily, in three areas. The first research area concerns the thermodynamic properties of modest size clusters. This work involves accurate quantum chemical determination of the total interaction energy for various cluster geometries followed by simulation of the dynamics of motion on the energy surfaces. The second area concerns the study of reactions on a Si surface. For this work, finite clusters are being used to model the motion and reaction of adsorbates on and with the surface. Finally, research is being carried out to validate and to extend various theoretical methods which are used for the study of larger molecules and clusters. Theoretical electronic structure methods have been firmly established and are regularly applied at two extremes; at one extreme are small systems composed of only a few atoms and at the other extreme are crystalline solids. The work under this grant deals with the intermediate case of clusters which are being studied for two scientific purposes. The first reason is to examine the properties of matter in the intermediate state between the extremes; this state is especially important because it has properties which are fundamentally different from those at the extremes. The work under this grant is helping to explore these fascinating and potentially useful cluster properties. The second reason is to study the properties of the surfaces of solids with suitable cluster models. Such models are especially useful to elucidate surface chemistry because they enable theory which explains and predicts chemistry in molecules to be applied to processes which occur at the surfaces of condensed matter.