## Abstract

We have developed a database of 29 molecules for which we have estimated the complete-one-electron-basis-set limit of the zero-point-exclusive atomization energy for five levels of electronic structure theory: Hartree-Fock (HF) theory, Møller-Plesset second- and fourth-order perturbation theory, coupled cluster theory based on single and double excitations (CCSD), and CCSD plus a quasiperturbative treatment of triple excitations [CCSD(T)], all at a single set of standard geometries. Convergence checks indicate that the estimates are within a few tenths of a kcal/mol of the n = infinity limit of the cc-pVnZ basis set sequence. This data is then used to obtain optimized power-law exponents for extrapolating to the basis-set-limit from correlation-consistent polarized valence double and triple zeta (cc-pVDZ and cc-pVTZ) basis sets. This allows one to get thermochemical accuracy comparable to polarized quadruple or quintuple zeta (cc-pVQZ or cc-pV5Z) basis sets with a cost very comparable to polarized triple zeta, which is one order of magnitude less expensive than polarized quadruple zeta and two orders of magnitude less expensive than polarized quintuple zeta.

Original language | English (US) |
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Pages (from-to) | 2921-2926 |

Number of pages | 6 |

Journal | Journal of Chemical Physics |

Volume | 111 |

Issue number | 7 |

DOIs | |

State | Published - Aug 15 1999 |