News Note

Parallel Quantum Chemistry Calculations

Researchers at Sandia National Laboratories are using IBM's new ASCI Blue-Pacific SST computer to perform the largest first-principles quantum chemistry calculations ever done. The emerging role of quantum chemistry as an important tool in chemical and biological research was illustrated by the 1998 Chemistry Nobel Prize award to one of the founders of quantum chemistry, John Pople. However, to fulfill its ultimate promise, quantum chemical calculations must be made feasible for much larger chemical problems. An important step towards this goal has been achieved by the implementation on IBM's ASCI Blue-Pacific SST computer of a parallelized quantum chemistry program (MPQC) under development at Sandia by Drs. Curtis Janssen, Ida Nielsen, and Matt Leininger. The initial application of MPQC is to a chemical problem that provides an important validation of less accurate chemical calculations and demonstrates the utility of large-scale quantum chemical calculations for applications in materials science, biochemistry, and environmental cleanup. The calculation being performed involves second-order Moeller Plesset Perturbation Theory (MP2), a method that has proved very accurate in predicting the structure and energy of molecules, but has been impractical for larger chemical systems. The first application was an MP2 calculation of the binding energy of the water trimer. Accurate binding energies are needed to calibrate approximate models of water, which are sufficiently inexpensive to permit modeling of bulk water. The calculation used an unprecedented 1329 basis functions and was the largest MP2 calculation ever performed.

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