DOI: 10.1063/1.2817618 ISSN:
A simple and efficient CCSD(T)-F12 approximation
Thomas B. Adler, Gerald Knizia, Hans-Joachim Werner- Physical and Theoretical Chemistry
- General Physics and Astronomy
A new explicitly correlated CCSD(T)-F12 approximation is presented and tested for 23molecules and 15 chemical reactions. The F12 correction strongly improves the basis set convergence of correlation and reaction energies. Errors of the Hartree-Fock contributions are effectively removed by including MP2 single excitations into the auxiliary basis set. Using aug-cc-pVTZ basis sets the CCSD(T)-F12 calculations are more accurate and two orders of magnitude faster than standard CCSD(T)/aug-cc-pV5Z calculations.