Theoretical Studies of the Liquid State

芝加哥大学的David Oxtoby教授得到了理论和计算化学项目的资助，继续他在成核理论研究方面的研究。Oxtoby使用统计力学技术，特别是密度泛函方法，探索与液体有关的相变：液体从蒸汽中冷凝，液体结晶形成固体。这些相变的速率主要取决于形核过程，即在现有亚稳相的中心首次出现新相的过程。Oxtoby的工作试图应用新的理论方法来预测从障碍到新相形成的关键核的形成速度和原子结构。Oxtoby发展的理论方法将既适用于液体从气体中成核，也适用于晶体固体从液体中成核。液体从气体中成核的一个常见的例子是云中水蒸气的冷凝。目前人们对极地平流层云的形成有相当大的兴趣，人们认为极地平流层云在两极上空臭氧耗尽的过程中起着关键作用。在所有这样的过程中，必须克服的第一个障碍是形成关键的核，然后其他分子在其上凝聚。奥克斯托比的研究将导致对此类体系中成核事件的理论分子水平的解释。

Professor David Oxtoby, University of Chicago, is supported by a grant from the Theoretical and Computational Chemistry Program to continue his research in theoretical studies of nucleation. Oxtoby uses techniques of statistical mechanics, specifically density functional methods, to explore phase changes involving liquids: the condensation of liquids from the vapor and the crystallization of liquids to form solids. The rates of these phase changes depend critically on the process of nucleation, the first appearance of a new phase at the center of an existing metastable phase. Oxtoby's work seeks to apply new theoretical approaches to predict the rates of formation and the atomic structures of the critical nuclei that from the barrier to the formation of new phases. The theoretical approaches being developed by Oxtoby will be applicable to both the nucleation of liquids from gases and the nucleation of crystalline solids from liquids. A familiar example of nucleation of liquids from gases is the condensation of water vapor in clouds. There is considerable current interest in the formation of polar stratospheric clouds, which are thought to play a key role in the depletion of ozone over the poles. In all such processes, the first barrier which must be surmounted is the formation of critical nuclei on which other molecules then condense. Oxtoby's research will lead to a theoretical molecular level interpretation of the nucleation event in such systems.