NERSC Initiative for Scientific Exploration (NISE) 2009 Awards

Energy Landscape of Nanoclusters

De-en Jiang, Oak Ridge National Laboratory

Sponsoring NERSC Project: Computational study for chemistry of novel separations (m697), Principal Investigator: De-en Jiang, Oak Ridge National Laboratory

We propose to explore the energy landscape of nanoclusters by employing the density functional theory-based basin-hopping technique for global-minimum search. When atoms self-assemble into nanoclusters, they usually form a structure that is the most stable. Searching for this structure would greatly help understand and explain indirect experimental data, such as from mass spectrometry. Basin-hopping is a powerful technique for finding global minima (Wales, D. J.; Doye, J. P. K., J. Phys. Chem. A, 1997, 101: 5111-5116). It involves a constant-temperature Monte-Carlo simulation; at each step, a full geometry optimization is performed. For many clusters, the empirical potentials are simply not predictive enough, thereby requiring a first-principles method. Therefore, we propose using density functional theory (such as implemented in VASP) to do fast geometry optimization, to power the basin-hopping global minimum search. This new project is expected to explore a great chemical space of nanoclusters (with 50 atoms or less) and deliver many interesting discoveries.