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The CHARMM package contains the main program that typically runs on Linux or Apple iOS computers along with force field parameters and test cases. CHARMM is written in modern Fortran 95 and interfaces with other packages if available.

Parallel execution is supported via MPI and openMP.

GPU support is  is available natively via the DOMDEC-GPU module and via an interface to the openMM package.

Major versions are released yearly in two different flavors:

  • CHARMM is the academic version available here for free for academic users.
  • CHARMm is the commercial version available through Biovia.



B. R. Brooks, C. L. Brooks III, A. D. Mackerell, L. Nilsson, R. J. Petrella, B. Roux, Y. Won, G. Archontis, C. Bartels, S. Boresch A. Caflisch, L. Caves, Q. Cui, A. R. Dinner, M. Feig, S. Fischer, J. Gao, M. Hodoscek, W. Im, K. Kuczera, T. Lazaridis, J. Ma, V. Ovchinnikov, E. Paci, R. W. Pastor, C. B. Post, J. Z. Pu, M. Schaefer, B. Tidor, R. M. Venable, H. L. Woodcock, X. Wu, W. Yang, D. M. York, and M. Karplus: CHARMM: The Biomolecular simulation Program, J. Comp. Chem. 30, 1545-1615 (2009), 

The original CHARMM reference and a brief update are:

B. R. Brooks, R. E. Bruccoleri, B. D. Olafson, D. J. States, S. Swaminathan, and M. Karplus: CHARMM: A Program for Macromolecular Energy, Minimization, and Dynamics Calculations, J. Comp. Chem. 4, 187-217 (1983)

A. D. MacKerell, Jr., B. Brooks,C. L. Brooks, III, L. Nilsson, B. Roux, Y. Won, and M. Karplus: CHARMM: The Energy Function and Its Parameterization with an Overview of the Program, in The Encyclopedia of Computational Chemistry, 1, 271-277, P. v. R. Schleyer et al., editors (John Wiley & Sons: Chichester, 1998)

Please visit Google Scholar for a list of list of citations of the CHARMM program