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Tomás A. Arias and John D. Joannopoulos. Engeness, Torkel Dyrbaek, 1972- Massachusetts Institute of Technology. Dept. of Physics. Massachusetts Institute of Technology. Department of Physics 2005-08-24T22:08:50Z 2005-08-24T22:08:50Z 2003 2003 http://hdl.handle.net/1721.1/8023 52569466 Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2003. Includes bibliographical references (leaves 157-162). This work presents new ab initio approaches to materials physics. We first introduce the multiscale approach to determination of thermal properties and changes in free energy. With this approach one can perform thermal averaging of ensembles of states with ab initio methods, thus enabling ab initio calculations of free energy changes. We use this method to perform an ab initio calculation of the free energy of reconstruction in the 300 reconstruction of silicon. In the next chapters we introduce a completely new approach to electronic structure calculations, using a new, real-space bais set (wavelets) which enables all-electron calculations of complex systems. By eliminating the need for pseudopotentials for decsribing the core, one can for the first time access the true density functional energy of a system through systematic convergence. In the final chapter we combine this method with the generalized gradient approximation to perform calculations on high-pressure phases of boron. by Torkel D. Engeness. Ph.D. 162 leaves 10186394 bytes 10186152 bytes application/pdf application/pdf eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Physics. Multiscale ab initio approaches to materials physics Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="4adfaecd-b820-4b03-a053-1c21373f92b6"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Multiscale ab initio approaches to materials physics</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2003</PublicationDate> <Authors> <Author> <DisplayName>Engeness, Torkel Dyrbaek, 1972-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Physics.</Keyword> <Abstract>This work presents new ab initio approaches to materials physics. We first introduce the multiscale approach to determination of thermal properties and changes in free energy. With this approach one can perform thermal averaging of ensembles of states with ab initio methods, thus enabling ab initio calculations of free energy changes. We use this method to perform an ab initio calculation of the free energy of reconstruction in the 300 reconstruction of silicon. In the next chapters we introduce a completely new approach to electronic structure calculations, using a new, real-space bais set (wavelets) which enables all-electron calculations of complex systems. By eliminating the need for pseudopotentials for decsribing the core, one can for the first time access the true density functional energy of a system through systematic convergence. In the final chapter we combine this method with the generalized gradient approximation to perform calculations on high-pressure phases of boron.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>