Year: 2001
Type: book
Abstract: The rapid development of information technology is based an the continuing miniaturization of electronic devices as well as an the development of new materials and entirely new concepts . For further development, the understanding of growth and diffusion mechanisms an a microscopic scale is absolutely essential . Valuable insight can be gained using ab-initio computer simulations . Probably the most successful theory for solving the quantum mechanical manyparticle problem is the density functional theory (DFT) . In this thesis, a new ab-initio method for molecular dynamics within the framework of DFT was developed and implemented . It is strongly related to the projector-augmented-wave method (PAW) by P . Blöchl, but also includes elements of a pseudocharge method proposed by M . Weinert for the full-potential linearized augmented plane wave method (FLAPW) . Like the FLAPW-method, the PAW-method is an all-electron method . case, the hamiltonian takes quite a simple form using normconserving Kleinman-Bylander-type Vanderbilt pseudopotentials . The PAW-method allows for an of systems containing virtually those which require high numerical effort pseudopotentials (e .g . 2p-elements like oxygen or 3d-transitional metals like copper) . In addition, a higher accuracy compared to the pseudopotentialmethod can be obtained due to the improved description of the density in the spacial vicinity of the atoms . In the later similar to the one obtained when pseudopotentials or ultrasoft efficient calculation any element of the periodic table, including when treated using normconserving The method was implemented starting from the ab-initio molecular dynamics code EStCoMPP, which uses normconserving pseudopotentials . The new code allows for physical systems containing pseudopotential-atoms as well as atoms described using the PAW-formalism at the same time . A program for the generation of the PAW-datasets needed to describe a particular typa of atoms was developed as well . Essential ingredients of this datasets are localized atomic wavefunctions and projectors . A procedure was developed and tested which yields projectors leading to a numerically stable representation of the PAW-hamiltonian . Additional tools for checking the generated datasets were implemented, too .
Source: JuSER (Forschungszentrum Jülich)
Author: Kromen, W.
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7009089215