Polynitrogen/Nanoaluminum Surface Interactions
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 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
- Jun 01, 2007
- Accession Number
- ADP023743
Entities
People
- Dan C. Sorescu
- Jerry A. Boatz
Organizations
- Air Force Research Laboratory