hover to animate -- input script physical analog (start at 3:25) & explanation

LAMMPS is a classical molecular dynamics code, and an acronym for Large-scale Atomic/Molecular Massively Parallel Simulator.

LAMMPS has potentials for soft materials (biomolecules, polymers) and solid-state materials (metals, semiconductors) and coarse-grained or mesoscopic systems. It can be used to model atoms or, more generically, as a parallel particle simulator at the atomic, meso, or continuum scale.

LAMMPS runs on single processors or in parallel using message-passing techniques and a spatial-decomposition of the simulation domain. The code is designed to be easy to modify or extend with new functionality.

LAMMPS is distributed as an open source code under the terms of the GPL. The current version can be downloaded here. Links are also included to older F90/F77 versions. Periodic releases are also available on SourceForge.

LAMMPS is distributed by Sandia National Laboratories, a US Department of Energy laboratory. The main authors of LAMMPS are listed on this page along with contact info and other contributors. Funding for LAMMPS development has come primarily from DOE (OASCR, OBER, ASCI, LDRD, Genomes-to-Life) and is acknowledged here.

The LAMMPS WWW site is hosted by Sandia, which has this Privacy and Security statement.

• (5/13) Added triclinic support for PPPM and MSM and Ewald long-range solvers.
• (3/13) New fix phonon command for calculating dynamical matrices and phonon dispersion relations.
• (2/13) New fix rigid/small command for modeling large numbers of small rigid bodies more scalably in parallel.
• (2/13) New body package for working with generalized aspherical particles.
• (1/13) Pre-built LAMMPS executable available as a Ubuntu Linux package and Mac OS X package.
• (12/12) Significant features added to LAMMPS in the last quarter of 2012 include file-style variables, compute inertia/molecule, pair_style mie/cut, enhanced fix gcmc for molecules, pair_style mean/sw/spline, angle_style fourier, angle_style fourier/simple, angle_style quartic, dihedral_style fourier, dihedral_style nharmonic, dihedral_style quadratic, improper_style fourier, various improvements to the new kspace_style msm, an extension of kspace_style pppm to enable grid communication even when running on tiny sub-domains per processor, kspace_style pppm/disp for long-range LJ interactions, and the moltemplate molecular pre-processing package. See authors here and details here
• (11/12) Released a molecular version of GCMC.
• (10/12) Added the moltemplate molecular builder tool to the LAMMPS distro.
• (9/12) Significant features added to LAMMPS in the third quarter of 2012 include a 2-FFT option for kspace_style pppm, a new multilevel summation method long-range solvers kspace_style msm, fix rigid/npt and fix rigid/nph, a new Fortran wrapper on the LAMMPS library, compute erotate/sphere/atom, compute contact/atom, pair_style lj/cut/coul/dsf and coul/dsf, and a simplification of the Python interface to LAMMPS that now works entirely thru shared libraries. See authors here and details here
• (8/12) Added GPU benchmark data for the Titan Development supercomputer at ORNL (used to be Jaguar), with timings on up to 512 GPU-enabled nodes.
• (8/12) Added constant pressure options for simlulating rigid bodies in the NPT or NPH ensembles, via the fix rigid/npt and fix rigid/nph commands.
• (6/12) Significant features added to LAMMPS in the second quarter of 2012 include an option to have both kinds of restart file output simultaneously, compute group/group with kspace option, pair_style lcbop, fix restrain for bonds and angles, improper_style cossq, improper_style ring, fix colvars command and a USER-COLVARS package, read_dump command, added optional variable dependence to many commands, rerun command, USER-MOLFILE package and dump molfile command, faster TIP4P water potential, fix balance, fix rigid input of user-defined moments of inertia for overalpped rigid bodies, granular rigid bodies with the correct effective mass in the GRANULAR package, and pair_style bop. See authors here and details here
• (6/12) Added a static and dynamic load balance via the balance and fix balance commands, for use with problems where particles do not fill the simulation box uniformly.
• (6/12) Added rerun and read_dump commands to allow dump files to be reprocessed by LAMMPS.
• (5/12) Added a USER-COLVARS package and fix colvars command to interface LAMMPS to an open-source collective variables package for the calculation of potentials of mean force (PMFs) in various scenarios.
• (3/12) Significant features added to LAMMPS in the first quarter of 2012 include pair_style lj/smooth/linear, fix reax/c/bonds, angle_style dipole, dihedral_style table, more GPU-enabled pair styles in the GPU package, quit command, pair_style kim, pair_style meam/spline, pair_style beck, new forcezero linesearch method for minimization, change_box command, balance command, per-atom energy and virial tabulation for KSpace solvers, reworking of the accuracy criteria for Kspace solvers, and a general capability for building for Windows with packages, using Visual Studio. See authors here and details here
• (2/12) Added per-atom energy and virial tallying to the long-range PPPM and Ewald solvers used via the kspace_style command.
• (1/12) Added a pair_style kim to support use of potentials archived by the Knowlegebase of Interatomic Models (KIM) project.
• Old

This is work by Sergey Zybin (zybin at wag.caltech.edu) and collaborators at Caltech to model shock-induced instabilities in explosive materials which have heterogeneous features, such as defects or interfaces, using the ReaxFF force field.

The figure shows shock loading of PBX in a 3.6M atom model with a saw-tooth interface between RDX and its polymer binder. The color represents slip which is highest at the interface.

This paper has further details:

Elucidation of the dynamics for hot-spot initiation at nonuniform interfaces of highly shocked materials, Qi An, Sergey V. Zybin, William A. Goddard III, Andres Jaramillo-Botero, Mario Blanco, and Sheng-Nian Luo, Phys Rev B, 84, 220101 (2011). (abstract)