Research Program Overview
Short-lived reactive radicals and intermediate reaction complexes
are believed to play central roles in combustion, interstellar
and atmospheric chemistry. Due to their transient nature, such
molecules are challenging to study experimentally, and our knowledge
of their structure, properties and reactivity is consequently
quite limited. To expand this knowledge, we develop new theoretical
methods for reliable computer-based prediction of the properties
of such species. We apply our methods, as well as existing theoretical
approaches, to study prototype radical reactions, often in collaboration
with experimental efforts. These studies help to deepen understanding
of the role of reactive intermediates in diverse areas of chemistry.
At the same time, these challenging problems sometimes reveal
frontiers where new theoretical developments are needed in order
to permit better calculations in the future.
Electronic structure theory has emerged as a valuable counterpart
to direct experiments for the study of reactive species that may
not be easily characterized (if at all) in the laboratory. This
explosive growth has resulted in the awarding of the 1998 Nobel
Prize in Chemistry to two of the great pioneers of the field,
John Pople and Walter Kohn. Yet there are still fundamental challenges
remaining for electronic structure theory. Techniques that can
reliably treat excited states, reliably break chemical bonds,
and feasibly simulate molecules containing very large numbers
of electrons are either not yet available, or only beginning to
emerge. It is in these frontiers of electronic structure theory
that our research is focused. These issues are particularly relevant
to energy research through permitting better simulations and thus
better understanding of the mechanisms underlying combustion chemistry
and soot formation. Recent activities have been centered around
the application and development of accurate wavefunction-based
coupled cluster methods for the reliable description of reactive
molecules in their ground states, and time-dependent density functional
theory for the excited states of large unsaturated hydrocarbons,
including radical and ionized species.
Career scientists other than me: None (assuming this excludes
students and postdocs).
