Exploring Complex Chemistry and Nuclear Physics with Quantum Mechanics

Dr. Piotr Piecuch and his associates have used the resources of the HPCC to accurately model the behavior of the fundamental building blocks of matter, to explore previously unexplained experimental results, and to solve extremely large problems that are beyond the capability of normal systems. He has used the new methodology developed using the HPCC to expand the capabilities of the widely used GAMESS software package, a quantum chemistry software package.

Dr. Piecuch is a Professor of Chemistry who also has appointments in the Department of Physics and Astronomy as well as the National Superconducting Cyclotron Laboratory. Working with his associates, Drs. Marta Włoch and Armagan Kinal, and with his Ph.D. student, National Science Foundation Research Fellow Jeffrey R. Gour, they have developed ab initio quantum chemistry approaches called coupled cluster methods.

“We develop mathematical and computational methods that explain how complex chemical reactions take place and what the structure of the atomic nucleus is, and, using the HPCC, solve complex problems that could not be solved otherwise,” says Mr. Gour.

To do this research, Dr. Piecuch and his co-workers study atoms, molecules, and atomic nuclei ab initio – from first principles of quantum mechanics. They start from the constituent particles – electrons in atoms and molecules, protons and neutrons (nucleons) in nuclei – and interactions among these particles, and derive and program the corresponding mathematical equations. Using the HPCC’s resources, Dr. Piecuch and his associates are able to model large-scale systems beyond the capability of normal computers.

“HPCC’s computers are critical for the success of our research. Without them, we could only deal with relatively small molecular systems. Right now, we can study transition-metal nano-particles, of interest in catalysis, or molecular models of the active centers of metalloenzymes, at the fully quantum mechanical level of theory, using our best methods. This was not possible before creating HPCC,” Dr. Piecuch says.

His group has used the HPCC’s facilities to provide a detailed microscopic description of the mechanisms of important reactions in organic chemistry, perform unprecedented coupled cluster calculations to model the interaction between oxygen and metallo-enzymes, of importance in biochemistry, and carry out unprecedented coupled-cluster calculations for atomic nuclei. Dr. Piecuch’s group’s coupled cluster methods were also able to explain previously unexplained results in experimental data observed. These are just a few selected examples out of many.

“We invent methods,” says Dr. Piecuch. “We can develop mathematical and computational approaches that explain how chemical reactions take place, what is the frequency of light that molecules absorb, what the microscopic structure of atomic nucleus is, and, using the HPCC, solve complex problems in chemistry and physics that could not be solved otherwise.”

More information about Dr. Piecuch’s research can be found on his group's website.