Extension of the ReaxFF reactive force fields to transition metals and their interactions with first row elements.

 

Adri van Duin and William Goddard III

 

Over the last years we have seen significant progress in the development of reactive force fields, emperical methods that allow for reactive simulations on systems too large to be amenable to quantumchemical (QC) simulations. Using extensive databases, derived from quantumchemical simulations on small molecules and condensed phase systems and covering both ground state molecules and relevant reaction pathways, we initially developed reactive potentials for hydrocarbons (1). During this development we have found the ReaxFF hydrocarbon reactive potential to be highly transferable to other chemical systems. This led to the development of ReaxFF potentials for nitramines (2), silicon/silicon dioxide systems (3) and aluminium/aluminium oxides. Our current research is focusing on extending this method to allow simulation of catalysis in various chemical systems.

This ongoing research includes:

 

- Development of ReaxFF parameters for bulk transition metals (Mo, Ni, Pt, Zr) using QC-equation of state data on various polymorphs.

- Combination of the ReaxFF first-row element potentials with the transition metal force fields and testing of these combined potentials against a database of QC-data on small organometallic clusters.

  

We will present some highlights and applications from this research, including simulations on temperature-induced phase alterations in magic-number Ni-clusters, simulation of molybdenum oxides catalytic surfaces and application of a Ni/C reactive potential to buckyball growth.

 

(1) van Duin, A.C.T.; Dasgupta, S.; Lorant, F.; Goddard III, W.A. (2001) J. Phys. Chem. A 105, 9396.

(2) Strachan, A; van Duin, A.C.T.; Dasgupta, S.; Chakraborty, D.; Goddard III, W.A. (2002) submitted to Phys. Rev. Letters.

(3) van Duin, A.C.T.; Strachan, A.; Goddard III, W.A (2002) J. Phys. Chem. A., in print.