The Spartan Computational Methods. Spartan provides a wide range of computational methods in order to address the needs of educators, bench chemists, and professional molecular modelers. All methods are easily accessed via Spartan's seamless graphical interface, putting real computational power just a few clicks away.
   
Methods:
     
  Molecular Mechanics Molecular mechanics is presently the only practical method for calculations on very large molecules or for conformational searching on molecules with a large number of degrees of freedom. MMFF94, in particular, has proven to be a reliable and inexpensive tool for conformational analysis. Molecular mechanics models may be applied to molecules containing upwards of 1,000 atoms.

Both the SYBYL and MMFF94 force fields are supported. SYBYL extends throughout the entire Periodic Table while MMFF94 has been specifically parameterized to reproduce geometries and conformations of organic molecules and biopolymers.
     
  Semi-Empirical
Molecular Orbital
Semi-empirical models are the simplest of the quantum chemical schemes, and are useful for equilibrium and transition-state structure calculations. PM3, in particular, has proven to be a reliable tool for geometry calculations on transition metal inorganic and organometallic compounds. Semi-empirical models are applicable to molecules containing upwards of 100 atoms.

MNDO, AM1 and PM3 methods are supported. MNDO/d extensions for heavy main-group elements have been implemented and PM3 parameters for most transition metals are now available.
     
  Hartree-Fock
Molecular Orbital
Hartree-Fock models remain a mainstay for structure, energy and property calculations, in particular for organic molecules. They are applicable to molecules containing upwards of 50 atoms.
Supported are a variety of basis sets: STO-3G, 3-21G, 6-31G*, cc-pVDZ, cc-pVTZ and cc-pVQZ, with extensions for diffuse functions and/or additional polarization functions. Also supported are a variety of pseudopotentials for calculations on molecules incorporating heavy elements.