GAMESS (US)

GAMESS (US) is a computational chemistry software program that stands for General Atomic and Molecular Electronic Structure System. The original code split in 1981 into GAMESS (US) and GAMESS (UK) variants, which now differ significantly. GAMESS is maintained by the members of the Gordon research group at Iowa State University.

Capabilities
GAMESS (US) can perform a number of general computational chemistry calculations, including Hartree-Fock, Density functional theory (DFT), Generalized Valence Bond (GVB), and Multi-configurational self-consistent field (MCSCF). Correlation corrections after these SCF calcualtions can be estimated by configuration interaction (CI), second order Møller-Plesset perturbation theory, and coupled cluster theory. Solvent effect can be considered using discrete effective fragment potentials or continuum models (such as PCM). Relativistic corrections can be calculated, including third order Douglas-Kroll scalar terms.

While the program does not perform molecular mechanics, it can be interfaced with the TINKER code for molecular mechanics to do mixed molecular mechanics/quantum mechanics calculations. The Fragment Molecular Orbital method can be used to treat large systems, by dividing them into fragments.

It can also be interfaced with the valence bond VB2000 and XMVB programs and the Natural Bond Order (NBO) analysis program.