Multi-purpose Electronic Structure Package
Date
2010-10-29
Authors
Mir Mohammed, Assadullah
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Abstract
This dissertation uses the following well-known scientific computation programs: • Augmented Plane Wave (APW) Method • Linearized Augmented Plane Wave (LAPW) Method • Naval Research Laboratory's Tight Binding Method (NRL-TB) • Fitting Code To Find Tight-Binding Parameters (TBFIT) • Scalable Tight Binding Total Energy Evaluation Code (STATIC) • Tight Binding Molecular Dynamics. (TBMD) The output of some of these programs is often fed as input to other programs, sometimes by using some other programs. This dissertation first builds a tool that automates the entire process, provides a Graphical User Interface (GUI), facilitates storing the data in a reusable format, and provides means to view relevant information in plotted forms. All of the programs listed above are developed over past decades by various scientists at Naval Research Laboratory (NRL) using FORTRAN. This dissertation utilizes the time and effort investment already made and builds on it to provide an integrated, automated, and user-friendly software with a GUI. This software also has an integrated plotting component to it to display various charts. The results of a program are evaluated. The output is automatically scanned to get key quantities. These key quantities are fed to the next program as input. In case the previous program reports any errors, those errors are reported accordingly to the user and any further processing of computations is interrupted. Some of the programs mentioned above have an interactive interface. Thus a user has to answer a number of questions in order to initiate a calculation. If the user makes a mistake or wishes to alter one of the responses provided to the program's questions, the user has to cancel the calculation and start afresh. This software is capable to store all the specifications regarding a calculation. The software is able to read these specifications and start the calculation. This provides the user means to alter input at will and also means to store the input as reference for later comparisons. Using this newly created tool called Multipurpose Electronic Structure Package, the following research was conducted: • A new set of Tight-Binding parameters for Potassium are produced by fitting tight-binding parameter functions through results produced by APW, a firstprinciples technique. These parameters are then used to validate against the APW computational results and also to get additional quantities. They are also used to ensure that they would perform adequately in a Tight-Binding Molecular Dynamics (TBMD) setting. • A new study on Magnesium Oxide (MgO) is presented based on the APW firstprinciples technique. It computes total energy and enthalpy under varying pressure and estimates a pressure of 126 GPa when Mgo transitions from NaCl crystalline structure to CsCl crystalline structure. A limited comparative study is also provided. • First-principles based APW is again used to study three heavy metals that don’t exist in nature and are created in laboratories: Lawrencium, Rutherfordium, and Dubnium. The ground-state crystalline structure, lattice parameters, band energies, density of states, and ferromagnetism are discussed.
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Keywords
Potassium, Rutherfordium, Magnesium oxide, Dubnium, Lawrencium, Tight-binding