Gaussian3 theory using reduced MøllerPlesset order
Abstract
A variation of Gaussian3 (G3) theory is presented in which the basis set extensions are obtained at the secondorder MøllerPlesset level. This method, referred to as G3(MP2) theory, is assessed on 299 energies from the G2/97 test set [J. Chem. Phys. 109, 42 (1998)]. The average absolute deviation from experiment of G3(MP2) theory for the 299 energies is 1.30 kcal/mol and for the subset of 148 neutral enthalpies it is 1.18 kcal/mol. This is a significant improvement over the related G2(MP2) theory [J. Chem. Phys. 98, 1293 (1993)], which has an average absolute deviation of 1.89 kcal/mol for all 299 energies and 2.03 kcal/mol for the 148 neutral enthalpies. The corresponding average absolute deviations for full G3 theory are 1.01 and 0.94 kcal/mol, respectively. The new method provides significant savings in computational time compared to G3 theory and, also, G2(MP2) theory.
 Publication:

Journal of Chemical Physics
 Pub Date:
 March 1999
 DOI:
 10.1063/1.478385
 Bibcode:
 1999JChPh.110.4703C
 Keywords:

 31.15.Md;
 31.15.Ar;
 33.15.Ry;
 31.90.+s;
 Perturbation theory;
 Ab initio calculations;
 Ionization potentials electron affinities molecular core binding energy;
 Other topics in the theory of the electronic structure of atoms and molecules