Title :
First principles calculations of the chemisorption properties of nitro-containing molecules on the Al/sub 2/O/sub 3/(0001) surface
Author :
Sorescu, Dan C. ; Boatz, Jerry A. ; Thompson, Donald L.
Author_Institution :
Nat. Energy Technol. Lab., USDOE, Pittsburgh, PA, USA
Abstract :
First-principles calculations based on density functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption of nitromethane (NM) and 1,1-diamino-2,2-dinitroethylene (FOX7) molecules on the basal plane of /spl alpha/-Al/sub 2/O/sub 3/ crystal. The calculations employ a (2/spl times/2) supercell slab model and 3D periodic boundary conditions. Based on these calculations we have determined that both NM and FOX7 molecules can adsorb nondissociatively on the surface, with the most stable adsorption configurations parallel to the surface. The corresponding binding energies are found in the range 25.3-26.0 kcal/mol for NM and 35.6-48.3 kcal/mol for FOX7 depending on the relative molecular orientation and the corresponding surface sites. The minimum energy pathways for NM dissociation have been determined and a low energy pathway leading to H elimination with formation of adsorbed CH/sub 2/NO/sub 2/ and hydroxyl species has been identified. Additional calculations have focused on adsorption properties of aci-nitromethane tautomers and on description of the energetic pathways connecting adsorbed nitromethane molecule with these tautomers.
Keywords :
aerospace engineering; aerospace propulsion; chemisorption; chemistry computing; density functional theory; molecules; nitrogen compounds; rockets; 3D periodic boundary condition; FOX7 molecule; chemisorption property; density functional theory; first principles calculation; generalized gradient approximation; nitromethane molecule; supercell slab model; Aluminum; Boundary conditions; Combustion; Density functional theory; Propulsion; Rockets; Slabs; Solids; Space technology;
Conference_Titel :
Users Group Conference (DOD_UGC'04), 2004
Conference_Location :
Williamsburg, VA, USA
Print_ISBN :
0-7695-2259-9
DOI :
10.1109/DOD_UGC.2004.17