Ojwang, J. G. O. and van Santen, Rutger A. and Kramer, Gert Jan and van Duin, Adri C. T. and Goddard, William A., III (2009) Parametrization of a reactive force field for aluminum hydride. Journal of Chemical Physics, 131 (4). 044501. ISSN 0021-9606 http://resolver.caltech.edu/CaltechAUTHORS:20090817-144817541
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A reactive force field, REAXFF, for aluminum hydride has been developed based on density functional theory (DFT) derived data. REAXFF_(AlH_3) is used to study the dynamics governing hydrogen desorption in AlH_3. During the abstraction process of surface molecular hydrogen charge transfer is found to be well described by REAXFF_(AlH_3). Results on heat of desorption versus cluster size show that there is a strong dependence of the heat of desorption on the particle size, which implies that nanostructuring enhances desorption process. In the gas phase, it was observed that small alane clusters agglomerated into a bigger cluster. After agglomeration molecular hydrogen was desorbed from the structure. This thermodynamically driven spontaneous agglomeration followed by desorption of molecular hydrogen provides a mechanism on how mobile alane clusters can facilitate the mass transport of aluminum atoms during the thermal decomposition of NaAlH_4.
|Additional Information:||©2009 American Institute of Physics. Received 2 April 2009; accepted 26 June 2009; published 22 July 2009. This work was supported by the Advanced Chemical Technologies for Sustainability (ACTS), which is funded by Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO). J.G.O.O. acknowledges fruitful discussions with Jason Graetz and Andreas Zuttel. PACS 68.43.Nr Desorption kinetics 82.30.Lp Decomposition chemical reactions (pyrolysis, dissociation, and fragmentation) 82.60.-s Chemical thermodynamics 82.30.Hk Chemical exchanges (substitution, atom transfer, abstraction, disproportionation, and group exchange) 82.30.Fi Ion-molecule, ion-ion, and charge-transfer chemical reactions 61.46.Df Structure of nanocrystals and nanoparticles|
|Subject Keywords:||aluminium; aluminium compounds; charge exchange; density functional theory; desorption; heat of adsorption; hydrogen; nanoparticles; nanostructured materials; particle size; pyrolysis; reaction kinetics theory|
|Official Citation:||Parametrization of a reactive force field for aluminum hydride J. G. O. Ojwang, Rutger A. van Santen, Gert Jan Kramer, Adri C. T. van Duin, William A. Goddard, and III, J. Chem. Phys. 131, 044501 (2009), DOI:10.1063/1.3182853|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||George Porter|
|Deposited On:||08 Sep 2009 18:17|
|Last Modified:||26 Dec 2012 11:12|
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