This is the home page for the classical molecular dynamics code LAMMPS, an acronym for Large-scale Atomic/Molecular Massively Parallel Simulator. The current version of LAMMPS is 7 Jul 2009.

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. The last major release is 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.

• (11/09) Real-time visualization by hooking LAMMPS to VMD via a socket connection. See the fix imd command.
• (10/09) Added first accelerated dynamics technique to LAMMPS, namely the parallel replica dynamics (PRD) method of Art Voter, which can be invoked via the prd commmand.
• (10/09) Added a pre-built Windows executable for LAMMPS to the download page.
• (9/09) Addition of an atomic-to-continuum package for performing simulations that couple continuum finite elements to atoms.
• (8/09) Addition of first GPU-enabled pair_styles: pair_style lj/cut/gpu and pair_style gayberne/gpu.
• (7/09) Release of 7 Jul 2009 version of LAMMPS. Enhanced features include improvements to the energy minimizer, per-type and per-atom mass and size/shape, self-documenting format for dump files, and a more general fix rigid allowing for rigid bodies containing finite-size particles. New commands or new options on existing commands include compute heat/flux for Green-Kubo thermal conductivity, compute cna/atom, pair_style reax, fix box/relax, group delete, fix deform wiggle, fix evaporate, fix ttm, compute reduce/region, compute temp/profile, pair_style born/coul/long, and fix reax/bonds. See details here.
• (2/09) Addition of ReaxFF potentials with new pair_style reax command.
• (1/09) Release of 9 Jan 2009 version of LAMMPS. New features include a reworking of how variables and computes keep track of when they were invoked so as to be current between simulation runs, a new Peridynamics package for mesoscale modeling, auto-adjusting of the PPPM stencil when large numbers of processors are used, and an upgrade to the Hertzian granular pair_style for polydisperse systems. New commands or new command options include communicate cutoff, pair_style tersoff/zbl, fix indent plane fix wall/lj93 velocity, delete_atoms porosity, special_bonds options, fix bond/create, and fix bond/break. See details here.
• Old

This is work by Matt Lane, Gary Grest, Mike Chandross, and Mark Stevens (all at Sandia) and Chris Lorenz (King's College, London). They studied the interaction of water with self-assembled monolayers (SAMs). Investigations included water penetration of damaged SAMs and water diffusion properties in nanoconfinement. The first snapshot shows the effects of water on SAM coatings with various sized regions of damage. The second shows only the water during penetration. The third snapshot shows water in nanoconfinement between two planar SAMs.

These papers have further details:

Water in Nanoconfinement between Hydrophilic Self-Assembled Monolayers, J. M. D. Lane, M. Chandross, M. J. Stevens, G. S. Grest, Langmuir, 24, 5209-5212 (2008). (abstract)

Water Penetration of Damaged Self-Assembled Monolayers, J. M. D. Lane, M. Chandross, C. D. Lorenz, M. J. Stevens, G. S. Grest, Langmuir, 24, 5734-5739 (2008). (abstract)