Real Space Method for First Principles Calculation of Electronic, Magnetic, and Spectroscopic Properties of Halogen-Bridged Transition Metal Compounds

点击翻译按钮获取中文摘要

9520319 Wilkins This award is one made through the FY95 Computational Approaches to Real Materials competition. Funding is provided through the Divisions of Materials Research, Mathematical Sciences and Advanced Scientific Computing, as well as by the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate. The research combines algorithm and code development with materials theory to address important materials problems for which computational breakthroughs can produce large payoffs. As such, the research spans the strategic initiatives in High Performance Computing and Communications and Advanced Materials and Processing. The halogen-bridged transition-metal linear-chain compounds are unique in their wide chemical tunability with respect to their ground state and their energy gap. Momentum-space computation has indicated that these materials may have technological importance. Real space computation will allow much larger systems to be studied due to transitioning from calculations scaling as the cube of the number of particles being considered to those scaling linearly with the number of particles. The larger systems will enable more accurate optical properties to be calculated and enable accurate treatment of defects, including polarons and solitons, which will allow realistic calculations of optical and magnetic properties. Computational aspects of the work include development of specialized parallel sparse matrix algorithms; use and development of load-balancing heuristics; development of parallel disk-based algorithms for fast Fourier transforms and other matrix operations; and, use of shared data-space model such as provided by High Performance Fortran. Codes will be run on a variety of platforms. %%% This award is one made through the FY95 Computational Approaches to Real Materials competition. Funding is provided through the Divisions of Materials Research, Mathematical Sciences and Advanced Scientific C omputing, as well as by the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate. The research combines algorithm and code development with materials theory to address important materials problems for which computational breakthroughs can produce large payoffs. As such, the research spans the strategic initiatives in High Performance Computing and Communications and Advanced Materials and Processing. The research will focus on a class of materials called halogen-bridged compounds. These compounds can be readily modified by varying their structure and components in order to achieve desired electronic, optical and magnetic properties. Thus, they are Odesigner materials.O Present computational techniques only hint at these possibilities. The present research will develop computational techniques in order to deal with much more realistic systems of these compounds. Consequently, successful completion of this research will advance computation on state-of-the-art computers, will assist in fundamental understanding of the properties of these compounds and will enable the accurate design of a class of materials for a variety of applications. ***