Using modern computational methods Spartan can calculate many molecular properties. The Spartan philosophy has been to focus and highlight a well established list of ‘standard’ computational methods and to rigorously document performance of these methods against experimental data.
The full Spartan calculations list provides a useful summary of the many computational methods and sub-options that Spartan incorporates. Inside Spartan these methods are easy to select and apply.
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.
Hartree-Fock models are useful for predicting structure, energy and property calculations, in particular for organic molecules.
Density Functional Theory
Density functional theory models typically provide results of a quality comparable to conventional correlated models such as MP2, but at a cost only slightly greater than that of Hartree-Fock models. As such, they are particularly useful for high-quality structure, energy and property calculations, including calculations on transition-metal inorganic and organometallic compounds. Local density models and BP, BLYP, EDF1, EDF2, and B3LYP models are supported with the same basis sets and pseudopotentials as available for Hartree-Fock models.
MP2 is perhaps the simplest model to take reasonable account of electron correlation, and generally provides accurate descriptions of equilibrium structure, conformation and energetics of a variety of chemical reactions, including reactions where chemical bonds are broken. MP methods are supported for the same basis sets and pseudopotentials available for Hartree-Fock and density functional models. New in Spartan is the RI-MP2 model, providing nearly identical results to MP2 but with significant performance improvements: energy calculations an order of magnitude faster and structure calculations a factor of 3 times faster than conventional MP2. MP3 and MP4 models are available for single-point energy calculations only, as is a fast localized orbital variant of MP2. The same basis sets and pseudopotentials supported for Hartree-Fock are available.
Calculations on excited states may be performed using CIS, CIS(D), and TDDFT models in addition to the entire range of density functional models. The same basis sets and pseudopotentials supported for ground-state calculations are available.
A number of high-order correlated models are available for energy calculations only. These include CCSD, CCSD(T), OD, OD(T), QCISD, QCISD(T), QCCD, and QCCD(T) models, with the same basis sets and pseudopotentials available for Hartree-Fock, density functional and Møller-Plesset calculations.
Several recipes for obtaining highly accurate heats of formation are available, including the new T1 recipe that provides results within 3 kJ/mol of the (also available) G3(MP2) approach, but with performance several orders of magnitude faster than G3(MP2). Additional recipes include G2, G3.