My primary areas of research are theoretical chemistry, mathematical chemistry and computer chemistry. Secondary areas are computational biology, predictive toxicology and drug research.

Specific topics

Relativistic
quantum chemistry of molecules containing Ga-Lr and recently
discovered elements(104-118) Chemical applications of group theory,
graph theory, & artificial intelligence Applications of mathematics and
computers to toxicology, environmental chemistry and
bioinformatics.

Detailed Research Description

Relativistic Quantum Chemistry of very heavy and superheavy
molecules

The electronic and spectroscopic properties of molecules containing very heavy atoms and superheavy elements (104-118) are altered substantially by relativity. Spin-orbit interaction alters the spectroscopic properties to a significant
extent. We have developed a relativistic approach to calculate the
spectroscopic properties of molecules containing heavy atoms. In this approach
electron correlation and spin-orbit interaction are introduced simultaneously
through a spin-orbit configuration interaction method. Electronic and
spectroscopic properties of a number of very heavy molecules of atoms from
Ga-118 are being or have been investigated. Relativistic computations of
transition metal clusters, which are useful models for catalysis, are being
investigated. Chemisorption is modeled with cluster-adsorbent interactions.

We are modeling actinide complexes at geological and biological interfaces.
Our computational models provide new insight into actinide migration and
speciation in natural ground water critical to the environmental management of
high-level radioactive wastes originating from nuclear materials. We have been
investigating the molecules of superheavy elements 104-118 that have been
discovered at LBNL/LLNL and elsewhere.

We are interested in
the electronic structure of semi-conductor and main group clusters such
as GaxAsy, InxPy, InxSby, Gex, Snx, Pbx and so on. Spectroscopic properties of these clusters are being computed to aid in the assignment of
observed spectra or in predicting the spectra.

Chemical Applications of Group Theory

Group theory is a powerful tool
of algebra of symmetry that facilitates characterization of symmetry of molecules (rigid and non-rigid) and introduces great simplifications to several chemical problems of sterochemistry, quantum chemistry, chemical selectivity, chemical reacivity and spectroscopy. We are interested in group
theory and operator methods applied to non-rigid molecules, weakly bound van der
Waals complexes synthesized in supersonic nozzle expansion experiments, NMR,
ESR, NQR spectra of crystals exhibiting phase transition and multiple quantum
NMR spectra of molecules. Powerful operator methods of generalized wreath
product groups have been developed for these problems.

Chemical Applications of Graph Theory & Combinatorics

We have been
studying chemical applications of graph theory, combinatorics and
artificial intelligence. These applications include applications to
fullerene cages,computer-simulated spectra (NMR, ESR, etc.), dynamic stereochemistry,
enumeration of isomers, NMR signal patterns and computer applications to
chemistry.

Mathematical & Computational Applications to Biology

We have been
applying quantum chemically and topologically based techniques for predictive
toxicology, molecular similarity and drug design. Applications of bioinformatics
to the general areas of proteomics and genomics and biodescriptors are being
considered.