Gaussianhyphen;1 theory: A general procedure for prediction of molecular energies

摘要

A general procedure is developed for the computation of the total energies of molecules at their equilibrium geometries.Abinitiomolecular orbital theory is used to calculate electronic energies by a composite method, utilizing large basis sets (including diffusehyphen;sp, doublehyphen;dandfhyphen;polarization functions) and treating electron correlation by Moslash;llerndash;Plesset perturbation theory and by quadratic configuration interaction. The theory is also used to compute zerohyphen;point vibrational energy corrections. Total atomization energies for a set of 31 molecules are found to agree with experimental thermochemical data to an accuracy greater than 2 kcalthinsp;molminus;1in most cases. Similar agreement is achieved for ionization energies, electron and proton affinities. Residual errors are assessed for the total energies of neutral atoms.