We use ab initio Quantum Mechanical (QM) calculations to derive a force field that accurately describes the atomic interactions in BaTiO3 allowing, via Molecular Dynamics (MD), the simulation of thousands of atoms. A key feature of the force field (denoted ReaxFF) is that charge transfer and atomic polarization are treated self-consistently. The charge on each atom is separated into a core, des...

A parametrized reactive force field model for aluminum ReaxFF(Al) has been developed based on density functional theory (DFT) data. A comparison has been made between DFT and ReaxFF(Al) outputs to ascertain whether ReaxFF(Al) is properly parametrized and to check if the output of the latter has correlation with DFT results. Further checks include comparing the equations of state of condensed ph...

We have parametrized a reactive force field for NaH, ReaxFF(NaH), against a training set of ab initio derived data. To ascertain that ReaxFF(NaH) is properly parametrized, a comparison between ab initio heats of formation of small representative NaH clusters with ReaxFF(NaH) was done. The results and trend of ReaxFF(NaH) are found to be consistent with ab initio values. Further validation inclu...

First-principles-based force fields prepared from large quantum mechanical data sets are now the norm in predictive molecular dynamics simulations for complex chemical processes, as opposed to force fields fitted solely from phenomenological data. In principle, the former allow improved accuracy and transferability over a wider range of molecular compositions, interactions, and environmental co...

To enable large-scale reactive dynamic simulations of copper oxide/water and copper ion/water interactions we have extended the ReaxFF reactive force field framework to Cu/O/H interactions. To this end, we employed a multistage force field development strategy, where the initial training set (containing metal/metal oxide/metal hydroxide condensed phase data and [Cu(H(2)O)(n)](2+) cluster struct...

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 tha...

Ettringite is a hexacalcium aluminate trisulfate hydrate mineral that forms during Portland cement hydration. Its presence plays an important role in controlling the setting rate of the highly reactive aluminate phases in cement paste and has also been associated with severe cracking in cured hardened cement. To understand how it forms and how its properties influence those of hardened cement a...

in this work, the thermal reaction of aluminum (al) and nickel oxide (nio) was investigated by molecular dynamics simulations. some effective features of reaction such as reaction temperature, the reaction mechanism, and diffusion rate of oxygen into aluminum structure were studied. reaxff force field was performed to study the al/nio thermite reaction behavior at five different temperatures (5...

To make a practical molecular dynamics (MD) simulation of the large-scale reactive chemical systems of Li-H and Li-C, we have optimized parameters of the reactive force field (ReaxFF) for these systems. The parameters for this force field were obtained from fitting to the results of density functional theory (DFT) calculations on the structures and energy barriers for a number of Li-H and Li-C ...

The development of improved epoxy resins can be greatly facilitated using molecular dynamics (MD) techniques. Because molecular-level failure events can play a significant role in epoxy mechanical behavior, the reactive force field (ReaxFF) is an ideal tool for MD simulations of crosslinked epoxies. The results of this study demonstrate that mechanical stiffness and strength values predicted wi...