Theoretical Studies of the Liquid State

David Oxtoby教授，芝加哥大学，由理论与计算化学项目资助，继续他的成核理论研究。Oxtoby使用统计力学技术，特别是密度泛函方法，来探索涉及液体的相变：液体从蒸汽冷凝和液体结晶形成固体。这些相变化的速率主要取决于成核过程，即在现有亚稳相中心首次出现新相。Oxtoby的工作旨在应用新的理论方法来预测从势垒到新相形成的关键原子核的形成速率和原子结构。Oxtoby正在开发的理论方法将既适用于气体成核的液体，也适用于液体成核的结晶固体。液体由气体成核的一个熟悉的例子是云中水蒸气的凝结。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的消耗中起着关键作用。在所有这些过程中，必须克服的第一个障碍是临界核的形成，其他分子随后在其上凝聚。Oxtoby的研究将导致对这类系统成核事件的理论分子水平解释。

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.