GAMESS is a general-purpose ab initio molecular electronic structure program for performing SCF- and MCSCF-gradient calculations, together with a variety of techniques for post Hartree Fock calculations.
The program utilises the Rys Polynomial or Rotation techniques to evaluate repulsion integrals over s, p, d and f type Cartesian Gaussian orbitals.
Open- and Closed-shell SCF treatments are available within both the RHF and the UHF framework, with convergence controls provided through a hybrid scheme of level shifters and the DIIS method.
In addition generalised valence bond, complete active SCF, and more general MCSCF calculations may be performed. The analytic energy gradient is available for each class of wavefunction above.
Gradients for s and p Gaussians are evaluated using the algorithm due to Schlegel, while gradients involving d and f Gaussians utilise the Rys Polynomial Method.
Geometry optimisation is performed using a quasi Newton rank-2 update method, while transition state location is available through either a synchronous transit, trust region or hill-walking method.
Force constants may be evaluated by numerical differentiation.
xx xx Ab Initio core potentials are provided in both semi-local and non-local formalism for valence-only molecular orbital treatments.
Conventional CI (using th table driven selection algorithms within the framework of MRDCI calculations),Direct-CI and Full-CI correlation treatments are available.

Source: This program is the european version of GAMESS, GAMESS-UK, maintained by M.F. Guest et al., (c) 1994 Computing for Science Ltd.
With courtesy of Dr. J. van Lenthe, Department of Theoretical Chemistry, Utrecht University, where documentation is maintained on a WWW server.

On-line documentation is also available by selecting (highlighting) GAMESS in the CAOS/CAMM menu and pressing the ? key.

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