Polynitrogen/Nanoaluminum Surface Interactions (Challenge Project C2V) (Preprint)
Abstract
First-principles density functional theory (DFT) calculations using the generalized gradient approximation (GGA) have been conducted to study the adsorption of a series of high-nitrogen compounds of increasing sizes and complexity on the Al(111) surface. The calculations employ periodic slab models with 4 Al layers, ranging in size from (3x3) to (7x7) surface unit cells, and containing up to 196 Al atoms. Complementary quantum chemical calculations, utilizing DFT and second-order perturbation theory methods, of the ground state potential energy surfaces of the corresponding polynitrogen/high nitrogen species in the absence of the aluminum surface also have been performed. For the set of chemical species Nx(x=1,5), NHx(x=1-3), N2Hx(x=1-4) and N3H, N3H3 and N4H4 the adsorption configurations at different surface sites and the corresponding binding energies have been determined. This analysis has been further extended to high-nitrogen compounds N5H and N6H2. For these two systems it was found that the initial bonding to the surface takes place through a molecular mechanism (nondissociatively) with involvement of single or multiple N atoms of the molecule. However, dissociation on the surface can take place with small activation energies. This set of calculations has been further extended to include 1,3,5-triazene and 1,2,3-triazine (C3H3N3) as well as larger substituted triazene systems such as C9N30 and C15N18. For these large systems it was found that bonding takes place through multiple N centers with formation of highly strained and deformed adsorption configurations. In a number of instances the adsorption takes place dissociatively with N2 elimination.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 08, 2007
- Accession Number
- ADA471116
Entities
People
- Dan C. Sorescu
- Jerry A. Boatz
Organizations
- Air Force Research Laboratory