PNNL

The Greek philosopher Democritus (b. 460 BC) proposed atoms as the smallest pieces of matter that cannot be divided further. Subsequently, Sir Isaac Newton (1642–1726) proposed the existence of “forces” holding macroscopic particles together. Such insight by Newton, as well as Robert Boyle (1627–1681) , provided the steppingstone for Dalton’s atomic theory of matter (1804) which among others stated that “atoms of different elements can combine in simple whole number ratios to form chemical compounds”, all hinting at the idea of a chemical bond. Today, the simulation capabilities of powerful supercomputers at the Department of Energy’s Leadership Computing Facilities, such as the exascale computer Frontier, and the National Science Foundation, such as Blue Waters, reveal previously unknown characteristics of chemical bonds at the quantum level.

A new special issue of The Journal of Chemical Physics illustrates the current state of chemical bond research. An invited editorial, co-authored by Pacific Northwest National Laboratory (PNNL) and Iowa State University (ISU) scientists, provides an overview of the research included in the special issue. PNNL Laboratory Fellow and University of Washington (UW) joint appointee Sotiris Xantheas, UW professor and PNNL Battelle Fellow Thomas Dunning, and ISU Distinguished Professor Mark Gordon were the guest editors of that special issue and co-authored the editorial.

The editorial summarizes the research topics discussed in the special issue of the journal, including the physical nature and characteristics of the chemical bond, chemical reactions, molecular interactions, and computational approaches.

“Technological advances in hardware coupled with innovative algorithms have unlocked new potential in computational chemistry,” said Xantheas. “Integrating machine reasoning and artificial intelligence with heterogeneous computing systems can further advance these studies.”

PNNL possesses over 30 years of experience in computational chemistry, from pioneering work integrating theory and experimentation through the Condensed Phase and Interfacial Molecular Science program, to the newly-established Computational and Theoretical Chemistry Institute (CTCI) for scalable computational chemistry software and methods development. Xantheas is the Director of CTCI and Dunning serves on its advisory board.

Xantheas, Dunning, and Gordon each work toward adapting current software suites for computational chemistry—such as the Center for Scalable Predictive Methods for Excitations and Correlated Phenomena (SPEC) libraries, NWChem, and GAMESS—for use on exascale systems.

“New hardware systems require rewriting the software so it can scale and run efficiently,” said Xantheas. “But the effort is worthwhile—bigger, faster simulations can be performed on exascale systems to more accurately predict the energetics and dynamics of chemical bonding in complex systems.”

Xantheas and Dunning are supported by the DOE, Office of Science, Basic Energy Sciences (BES), Chemical Sciences, Geosciences and Biosciences (CSGB) program, SPEC. Xantheas is also supported by the BES-CSGB Condensed Phase and Interfacial Molecular Science program. Gordon is supported by the DOE Exascale Computing Project at Ames National Laboratory.