冰表面小分子吸附与扩散过程的动力学研究

项目名称： 冰表面小分子吸附与扩散过程的动力学研究

项目编号： No.11274012

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 王恩哥

作者单位： 北京大学

项目金额： 71万元

中文摘要： 广泛存在自然界中的冰，在大气环境、生命科学等领域起着重要的作用。虽然人们对体相冰的研究一直表现了极大兴趣，但目前主要工作仍旧停留在宏观半经验的水平上,而有关冰表面研究才只是刚刚开始。最近我们在原子尺度上发现并提出了冰表面序参量的概念，证明冰表面氢原子更趋向于有序分布。从实际情况来看，冰表面氢原子悬挂键在各处的排列仍存在一定涨落性，这是导致冰表面的预融化、吸附、生长等复杂而奇特现象的根本原因。此外，现有研究冰表面的实验手段，如低能电子衍射(LEED)、氦原子散射(HAS)等，却因为氢原子的踪迹太小而难以给出准确直接的信息。因此从计算物理的角度研究冰表面序参量与各种分子在冰表面的动力学过程之间的关系尤为重要。本项目提出从第一性原理和半经验势分子动力学模拟两种途径出发，对水分子及高空大气中其它分子在冰表面的吸附和扩散过程进行系统研究，以期在原子分子尺度上揭示冰表面各种现象的物理本质。

中文关键词： 冰表面；分子吸附与扩散；冰晶生长；第一性原理；分子动力学

英文摘要： Ice, one of the most common materials in nature, plays an important role in interstellar phenomenon, global climate and life in cryosphere. Despite bulk ice being a well-studied substance, it is surprising that our knowledge of ice surface is still an open question. Very recently, we proposed a proton order parameter for ice surface, and found that, although bulk ice is a proton disordered solide, at the surface, protons are more ordering. However, at large scale, the distribution of OH dangling bonds on ice surface is not uniform, which suggests that the relation between the ice surface order parameter and its premelting/adsorption process is more complex and novel than expected. Besides, the current experimental technologies, such as the low-energy electron diffraction (LEED) and helium atom scattering (HAS),can hardly determine the arrangement of protons on the ice surface because their footprint is too tiny to be captured. Thus, theoretically understanding the relation of the arrangement of protons on ice surface and the adsorption process as well as the growth of ice is of great importance. By means of first principles total-energy calculations and empirical molecular dynamics simulations, we propose here to firstly study the influence of proton order on the adsorption of water monomer and other high altitu

英文关键词： ice surface；molecular adsorption and difussion；ice growth；first-principle calculation；molecular dynamics