

Research Expertise and Interest
theoretical chemistry, electronic structure calculations, development of novel theories and algorithms, quantum mechanics
Research Description
Professor Head-Gordon's group performs research on the development and application of electronic structure theories, to permit the treatment ofproblems that are currently beyond the reach of standard methods. The electronic structure problem is to calculate the properties of a molecule from first principles quantum mechanics, with the objective of obtaining information on structure and reactivity. Since this information is crucial to understanding and controlling the chemistry of molecules, applications of electronic structure theory play an important and growing role in many areas of chemistry.
At the same time, there are fundamental problems with the currentstandard electronic structure methods. Standard theories are notcapable of correctly breaking chemical bonds or describing darkexcited states that control photochemistry, without resorting tospecialist multireference methods. Standard electronic structuremethods have computational costs that rise as unphysically steep powers of the number of atoms in the molecule. This makes applicationto large molecules and molecular assemblies unfeasible at present,particularly with the most accurate methods. Additionally thereis a need to bridge the large gulf that exists betweeen the methodsby which electronic structure calculations are performed and theway in which the physical insight is extracted from the calculations.
Professor Head-Gordon and his group are performing research thataims to address issues such as those identified above, to buildthe next generation of electronic structure theories. This researchcombines fundamental quantum mechanics and many-body theory withaspects of applied mathematics and numerical analysis, as well ashigh performance computing. Exciting progress has been made overthe last few years in linear scaling methods for density functionaltheory, new approaches to describing the correlations betweenelectrons in spatially localized terms, and new model chemistries forground and excited states. Additionally, challenging chemicalapplications are performed in diverse areas of chemistry to exploitnew theoretical developments, and to further probe the limitationsof standard methods. These studies are often in collaborationwith experimental studies, and recent examples have been in the areasof combustion and interstellar chemistry.