| 초록 |
The reactive force field, ReaxFF, developed by van Duin and co-workers make feasible for the simulations of nanoscale dimensions for nanoseconds with bond-making and bond-breaking reactions which lack in classical MD simulations. In this study, a new ReaxFF force field parameters have been developed to describe ammonia synthesis process in the Ru-N-H system. The ReaxFF force field parameters have been fitted to a quantum mechanical (QM) training set containing structures and energies related to bond dissociation energies, angle and dihedral distortions, and reactions between N2/H2 and Ruthenium as well as N2 and H2 dissociation pathway on Ruthenium 001 surface, equation of state of Ruthenium and migration energy barrier of H and N on Ruthenium surface. Model configurations for the training set were based on DFT calculations on molecular clusters and periodic systems (both bulk crystals and surfaces). ReaxFF reproduces accurately the QM training set for structures and energetics of small clusters. The results of ReaxFF match reasonably well with those of QM for binding energies, surface energies and dissociatioin/association energy barriers of N2/H2 and NH/NH2/NH3, respectively. |
