ReaxFF_MgH Reactive Force Field for Magnesium Hydride Systems Export

@article{citeulike:1099400, abstract = {Abstract: We have developed a reactive force field (ReaxFFMgH) for magnesium and magnesium hydride systems. The parameters for this force field were derived from fitting to quantum chemical (QM) data on magnesium clusters and on the equations of states for condensed phases of magnesium metal and magnesium hydride crystal. The force field reproduces the QM-derived cell parameters, density, and the equations of state for various pure Mg and MgH2 crystal phases as well as and bond dissociation, angle bending, charge distribution, and reaction energy data for small magnesium hydride clusters. To demonstrate one application of ReaxFFMgH, we have carried out MD simulations on the hydrogen absorption/desorption process in magnesium hydrides, focusing particularly on the size effect of MgH2 nanoparticles on H2 desorption kinetics. Our results show a clear relationship between grain size and heat of formation of MgH2; as the particle size decreases, the heat of formation increases. Between 0.6 and 2.0 nm, the heat of formation ranges from -16 to -19 kcal/Mg and diverges toward that of the bulk value (-20.00 kcal/Mg) as the particle diameter increases beyond 2 nm. Therefore, it is not surprising to find that Mg nanoparticles formed by ball milling (20-100 nm) do not exhibit any significant change in thermochemical properties.}, address = {Materials and Process Simulation Center, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125}, author = {Cheung, S. and Deng, W. Q. and Vanduin, A. C. T. and Goddard, W. A.}, citeulike-article-id = {1099400}, citeulike-linkout-0 = {http://dx.doi.org/10.1021/jp0460184}, citeulike-linkout-1 = {http://pubs.acs.org/doi/abs/10.1021/jp0460184}, day = {10}, doi = {10.1021/jp0460184}, journal = {J. Phys. Chem. A}, keywords = {h, mg, reaxff}, month = {February}, number = {5}, pages = {851--859}, posted-at = {2007-02-10 19:34:42}, priority = {2}, title = {ReaxFF_MgH Reactive Force Field for Magnesium Hydride Systems}, url = {http://dx.doi.org/10.1021/jp0460184}, volume = {109}, year = {2005} }

TY - JOUR ID - citeulike:1099400 L3 - citeulike-article-id:1099400 N2 - Abstract: We have developed a reactive force field (ReaxFFMgH) for magnesium and magnesium hydride systems. The parameters for this force field were derived from fitting to quantum chemical (QM) data on magnesium clusters and on the equations of states for condensed phases of magnesium metal and magnesium hydride crystal. The force field reproduces the QM-derived cell parameters, density, and the equations of state for various pure Mg and MgH2 crystal phases as well as and bond dissociation, angle bending, charge distribution, and reaction energy data for small magnesium hydride clusters. To demonstrate one application of ReaxFFMgH, we have carried out MD simulations on the hydrogen absorption/desorption process in magnesium hydrides, focusing particularly on the size effect of MgH2 nanoparticles on H2 desorption kinetics. Our results show a clear relationship between grain size and heat of formation of MgH2; as the particle size decreases, the heat of formation increases. Between 0.6 and 2.0 nm, the heat of formation ranges from -16 to -19 kcal/Mg and diverges toward that of the bulk value (-20.00 kcal/Mg) as the particle diameter increases beyond 2 nm. Therefore, it is not surprising to find that Mg nanoparticles formed by ball milling (20-100 nm) do not exhibit any significant change in thermochemical properties. IS - 5 JF - J. Phys. Chem. A AD - Materials and Process Simulation Center, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 EP - 859 TI - ReaxFF_MgH Reactive Force Field for Magnesium Hydride Systems VL - 109 SP - 851 KW - h KW - mg KW - reaxff AU - Cheung, S AU - Deng, WQ AU - Vanduin, ACT AU - Goddard, WA PY - 2005/02/10/ UR - http://dx.doi.org/10.1021/jp0460184 ER -