Presidential Young Investigator Award

这笔PYI赠款将启动两个项目：一个涉及改进电子结构的从头算紧束缚代码，另一个涉及表面预熔化。在第一个项目中，拟议的使用定域轨道的代码改进承诺极快地计算多达200个原子的系统的分子动力学。该方法目前可以处理S轨道和p轨道，但将扩展到处理d轨道，以便可以计算过渡元素的性质。改进后的程序将用于研究聚合物-金属界面的粘附性和纳米级金属团簇的结构。表面预熔的研究将集中在铅上。有效原子法将被用来计算大块固体和大块液体的吉布斯自由能；熔点将从这些信息中得到。在低于熔点的温度范围内，分子动力学将被用来模拟几个铅表面。在这笔总统青年研究员补助金中，将启动两个理论材料科学项目。第一个将涉及改进计算机代码，以处理在许多应用中非常重要的过渡金属。这个改进后的代码将被用于研究聚合物-金属界面的粘附性和纳米级金属团簇的结构。对铅表面预熔的研究将有助于我们更好地理解为什么金属表面经常在块状材料熔化之前熔化。这对各种应用的金属加工有重要的影响。

Two projects will be initiated on this PYI grant: one involves improving ab-initio tight binding code for electronic structure and the other deals with pre-melting at surfaces. In the first project, the proposed code improvements using localized orbitals promise extremely fast calculations of the molecular dynamics of systems with up to 200 atoms. The method can presently handle s- and p-orbitals, but will be expanded to deal with d-orbitals so that transition element properties can be calculated. The improved code will be used to study adhesion at polymer-metal interfaces and the structure of nanoscale metallic clusters. The study of pre- melting of surfaces will focus on lead. The effective atom method will be used to calculate the Gibbs free energy of the bulk solid and the bulk liquid; the melting point will be obtained from this information. For a range of temperatures below the melting point molecular dynamics will be used to simulate several lead surfaces. %%% On this Presidential Young Investigator grant two projects in theoretical materials science will be initiated. The first will involve the improvement of a computer code to deal with transition metals which are important in many applications. This improved code will then be used to study adhesion at polymer-metal interfaces and the structure of nanoscale metal clusters. The study of the pre-melting of lead surfaces will improve our understanding of why the surfaces of metals often melt prior to the melting of the bulk materials. This has important ramifications in the processing of metals for a variety of applications.