Molecular Models Applied to the Heterogeneous Nucleation of Ice: Ice Formation on Surfaces

Barbara Hale教授将应用水/冰系统的计算机模型和比例成核率形式论来研究非均相成核。其目标是从微观基质属性的角度描述天然大气和人造冰核的成冰特征，并开发提供微观基质属性的解析式和提供阈值温度和非均相成核速率的方便估计的解析式。具体地说，在模型衬底(例如模型碘化银基面和模型羟化二氧化硅表面)和具有改性水的衬底上的吸附水层中冰形成的阈值温度将被检查衬底相互作用的影响：(1)衬底晶格结构，(2)水。衬底结合能，(3)衬底台阶缺陷，(4)外加电场和压力脉冲扰动；(5)凝结水层厚度。计算机模拟使用有效的水-水和水-衬底原子对势和蒙特卡罗技术来生成水/冰吸附系统热力学的正则系综平均值。这项工作很重要，因为它提供了非均相相变机制的定量描述，特别是冰相的形成。

Professor Barbara Hale will apply computer models of water/ice systems and a scaled nucleation rate formalism to the study of heterogeneous ice nucleation. The goals are to characterize ice nucleating features of natural atmospheric and artificial ice nuclei in terms of microscopic substrate properties and develop analytic the which provide microscopic substrate properties and develop analytic the which provide convenient estimates of threshold temperatures and heterogeneous nucleation rates. Specifically, threshold temperatures for ice formation in adsorbed water layers on model substrates (such as a model silver iodide basal face and a model hydroxylated silica surface) and on substrates with modified water.substrate interactions will be examined for effects of: (1) substrate lattice structure, (2) water.substrate binding energy, (3) substrate ledge defects, (4) external electric field and pressure pulse perturbations, and (5) thickness of the condensed water layers. The computer simulations use effective water.water and water.substrate atomic pair potentials and Monte Carlo techniques to generate canonical ensemble averages of thermodynamic quantities for the adsorbed water/ice systems. This work is important because it provides quantitative descriptions of the heterogeneous phase change mechanism, in particular, the ice phase formation.