Theoretical studies of the electronic structure and energetics of condensed matter

点击翻译按钮获取中文摘要

The electrons in a solid or liquid, or a molecule form the glue that hold the atoms together and determine the microscopic arrangement of the atoms, and ultimately the large scale structural properties. The electrons move according to quantum mechanics, and interact with one another and with the slow moving ions. The total energy of this complex system of many interacting particles determines the forces acting on the atoms, and consequently how they move and where they prefer to reside. This work investigates ways to deal with the electrons so that energy and forces can be calculated with existing computing power and with enough accuracy to allow prediction of materials properties. We propose to investigate the electron kinetic energy with the aim of developing an accurate but efficient way of treating it, as this contribution to the energy is presently a bottleneck in the methods. The methods are used to study the properties of systems which are of basic scientific interest, and materials which have useful electronic or structural properties. Two examples of systems of interest are: (i) Natural animal bone and synthetic bone are calcium phosphates containing various inpurities that influence the bioactivity. We have developed unique expertise in simulating these materials and will next focus attention on the nature of the interfaces between these materials and body fluid which is where biological action takes place. (ii) Regular arrays of clusters of a few atoms can form on an exposed silicon surface. These "magic" clusters are intersting in themselves and may have device applications. There are indications that magic clusters may also form on a germanium surface. We propose to investigate the way they might form and their properties.