Research Interests
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My research interests focus on connecting ab initio electronic structure methods with thermodynamic and kinetic properties of matter. I use state-of-the-art electronic structure methods in combination with a wide variety of techniques from quantum mechanics to molecular dynamics, to solve relevant problems in chemistry, biophysics, and materials science.
FIRST-PRINCIPLES SIMULATIONS
The predictive capabilities of modern theoretical computational methods are significantly impacting chemical sciences. A possible example of this from my own research has been the use of first-principles electronic structure methods to predict structure and red-ox properties of ferrous center and systems of environmental interest e.g. nitrobenzene and trinitrotoluene. Although the experimental evidences are still limited, the iron (II) oxo-species are one of the most attractive NACs-reducing agents being extremely cheap and environmentally clean.1 1. a) I. Zilberberg, M. Ilchenko, O. Isayev, L. Gorb, J. Leszczynski. J. Phys. Chem. A, 2004, 108, 4878.
b) O. Isayev, L. Gorb, I. Zilberberg, J. Leszczynski. J. Phys. Chem. A, 2007, 111, 3571. On the other hand first-principles simulations applicable to a wide variety of problems, ranging from high-pressure physics to solvation chemistry, nanotechnology, and molecular biology. Of particular interest to me is the structure and dynamics of nucleic acid bases in water, mechanism of catalysis on ferrous and ferric centers, reactivity and transformations of substituted norbornene derivatives.
TOWARDS HIGH ACCURACY
Currently I am investigating the use of high-level post Hartree-Fock methods in the context of refining the procedure for calculations of Gibbs free energy with relative accuracy less than 1 kcal/mol.2 2. O. Isayev, L. Gorb, J. Leszczynski. J. Comp. Chem. 2007, 28, 1598. By combining these approaches together; by analyzing the effects of electron correlation, basis set size, and anharmonicity the new economic way to reach chemical accuracy in the calculations of the thermodynamic parameters for intermolecular interactions is proposed. I am presently employing this methodology for modeling of systems of biological and environmental interest. Also, I am exploring bridging of thermodynamic integration approach with Car-Parrinello molecular dynamics method for the same purpose.
HIGH-PERFORMANCE COMPUTING (HPC)
With the emergence of theoretical chemistry, biophysics and HPC, the scientific and technical opportunities in this field are enormous. As part of collaboration with the Army High Performance Computing Research Center (AHPCRC) my efforts are devoted to benchmarking and performance/functionality enhancements computational chemistry codes (e.g. CPMD) on the new Cray X1E and XT3 supercomputers, Opteron Linux Beowulf cluster systems. As part of collaboration with the Mississippi Center for Supercomputing Research (MCSR) I have been involved into testing, benchmarking and tuning some scientific applications for the 198 CPUs SGI Altix 3700 global shared-memory system.