MICCoM Codes


This website hosts the software suites SSAGES (Software Suite for Advanced General Ensemble Simulations) and COPSS (Continuum--Particle Simulation Software) which augment standard molecular dynamics and Monte-Carlo codes, permitting particle--field coupling (COPSS), calculation of reaction coordinates and reactive pathways, and free energies (SSAGES). Each presents not only a set of methods, but also aims to provide a unified, extensible framework adaptable to generic molecular simulations.

This site also hosts the GPU-accelerated molecular dynamics engine DASH. The engine is controllable through a powerful Python interface. DASH is specifically designed to couple with SSAGES for fast, state of the art advanced sampling calculations .

MICCoM codes SSAGES, COPSS, and DASH are open-source and distributed under the GNU General Public License (v3.0). These codes were developed at Argonne National Laboratory in conjunction with the University of Chicago and the University of Notre Dame.

MICCoM also supports the development of WEST and Qbox.

The Materials Science Division at Argonne National Laboratory (Building 241)

Seamless Integration

SSAGES and COPSS are designed from the ground up to connect to arbitrary molecular simulation codes through minimal programming effort. Initial releases target specific interoperability with open-source codes GROMACS and LAMMPS, and will grow to incorporate other open-source, proprietary, and bespoke codes.


SSAGES implements several methods for reactive pathway identification and free energy measurement, including Forward Flux Sampling, Metadynamics, and Nudged Elastic Band methods. A video showing the isomerization of alanine dipeptide is shown here, with all calculations having been performed in SSAGES.


The continuum--particle coupling provided by COPSS enables the spanning of multiple timescales in simulation. The initial suite of routines is built around the General-geometry Ewald-like Method (GgEM) which enables simulations such as that shown below, where a discrete polymer chain, representing DNA, is embedded in a background solvent, and confined to a nanoscopic channel; without coupling algorithms such as GgEM, such simulations are impossible.

The continuum--particle coupling of COPSS permits efficient simulation of many-body systems such as the DNA nanoslit (see video) on the timescales of polymer diffusion. In the first video, 84 kilobase DNA is simulated under confinement in a nanochannel with full hydrodynamic coupling to itself and the system boundaries.

COPSS also permits the simulation of electrostatic interactions with polarization effects in heterogeneous dielectric media in an accurate, highly efficient manner. In the second video, 10 polarizable micron-sized particles are simulated in an vacuum environment where only long-range electrostatic interaction and short-range excluded volume interaction affect their motion. The electrostatic forces are calculated by COPSS at each time step, and the particles' positions are evolved by coupling COPSS with LAMMPS.


DASH is a GPU-accelerated molecular dynamics software package designed for both atomistic and coarse grained simulations. DASH is controlled via a powerful Python interface, which gives the user full control to set up, modify, and analyze simulations all within one script. Using efficient parallel algorithms, DASH also provides the facility to compute arbitrarily complex user-defined types of data while maintaining high performance.

DASH is specifically optimized for running with the the advanced sampling package SSAGES, allowing up to double the performance of leading competitors. With plain molecular dynamics, performance in DASH is comparable to the fastest codes available.

DASH supports several water models including TIP3P, TIP4P (and variants), as well as the E3B model, a fast and robust 3-body water model parameterized to capture much of the water phase diagram (Kumar, JPC, 2008).

In addition to these features, DASH provides all the standard functionality users have come to expect from a batteries-included molecules dynamics package, including a variety of thermostats, barostats, elegant methods for dealing with molecules, long range charge computation, multiple force fields, and much more.