RAPTOR^® is an Open-Source software package for molecular dynamics simulations of chemical reactions in condensed phase. It is developed by the research group of Prof. Gregory A. Voth at Department of Chemistry, The University of Chicago. RAPTOR^® stands for Rapid Approach for Proton Transport and Other Reactions.

Chemical reactions are founded in quantum dynamics. This naturally suggests quantum mechanical simulation methodologies (e.g. ab initio MD or QM/MM), which explicitly simulate the electronic structure, as the ideal method to approach reactive systems. However, the computational expense of these methods strongly limits their applicability to anything but the smallest systems. This has led to the development of reactive molecular mechanics models, such as Multiscale Reactive Molecular Dynamics method (MS-RMD) developed by the Voth group, which faithfully emulate reactive electronic structure through dynamic bonding. Properly parameterized reactive methods such as MS-RMD have the ability to efficiently capture chemical reactivity at a fraction of the computational cost.

The MS-RMD methodology is implemented by the Voth group in RAPTOR^® as a plug-in package to LAMMPS, which is a popular molecular dynamics code developed by the Sandia National Laboratory. Therefore, RAPTOR^® is compatible with mosft of the features and functions of LAMMPS and can be used for large-scale simulations over hundreds CPU cores via MPI.