WFU Physics Colloquium

TITLE: Ph. D. Defense Presentation: "A survey of several van der Waals-rich systems and a machine learning approach to improving density functional theory"

SPEAKER: Brian Kolb,

TIME: Friday June 1, 2012 at 10:30 AM

PLACE: Room 101 Olin Physical Laboratory

Van der Waals interactions are weak, non-specific forces arising at the atomic scale. Although they are weak---much weaker than covalent or ionic interactions---they occur in number, and, in total, can make a significant contribution to the properties of a system. In the first part of this talk, several systems whose properties are influenced strongly by van der Waals interactions will be explored. These systems were investigated largely through the non-local van der Waals density functional (vdW-DF) working within density functional theory (DFT), with accurate quantum chemistry calculations and experimental results serving as a reference against which we compare our results. In the second part of this talk, the theoretical groundwork will be laid for a computational tool that uses network concepts to perform analytical calculations. These network functions are capable of learning the mathematical relationship buried in a set of data by utilizing a continuously variable functional form controlled via a set of trainable parameters. A course to use network functions to improve DFT through a search for a kinetic energy functional and an improved exchange-correlation functional will be discussed.