TY - JOUR
T1 - Simplified CCSD(T)-F12 methods
T2 - Theory and benchmarks
AU - Knizia, Gerald
AU - Adler, Thomas B.
AU - Werner, Hans Joachim
N1 - Funding Information:
This work was funded by the Deutsche Forschungsgemeinschaft in the priority program SPP 1145 (“Modern and universal first-principles methods for many-electron systems in chemistry and physics”). H.-J.W. is also grateful for generous support by the Fonds der Chemischen Industrie. We thank Fred Manby for providing the integral routines used in the density fitted F12 programs.
PY - 2009
Y1 - 2009
N2 - The simple and efficient CCSD(T)- F12x approximations (x=a,b) we proposed in a recent communication [T. B. Adler, G. Knizia, and H.-J. Werner, J. Chem. Phys. 127, 221106 (2007)] are explained in more detail and extended to open-shell systems. Extensive benchmark calculations are presented, which demonstrate great improvements in basis set convergence for a wide variety of applications. These include reaction energies of both open- and closed-shell reactions, atomization energies, electron affinities, ionization potentials, equilibrium geometries, and harmonic vibrational frequencies. For all these quantities, results better than the AV5Z quality are obtained already with AVTZ basis sets, and usually AVDZ treatments reach at least the conventional AVQZ quality. For larger molecules, the additional cost for these improvements is only a few percent of the time for a standard CCSD(T) calculation. For the first time ever, total reaction energies with chemical accuracy are obtained using valence-double- basis sets.
AB - The simple and efficient CCSD(T)- F12x approximations (x=a,b) we proposed in a recent communication [T. B. Adler, G. Knizia, and H.-J. Werner, J. Chem. Phys. 127, 221106 (2007)] are explained in more detail and extended to open-shell systems. Extensive benchmark calculations are presented, which demonstrate great improvements in basis set convergence for a wide variety of applications. These include reaction energies of both open- and closed-shell reactions, atomization energies, electron affinities, ionization potentials, equilibrium geometries, and harmonic vibrational frequencies. For all these quantities, results better than the AV5Z quality are obtained already with AVTZ basis sets, and usually AVDZ treatments reach at least the conventional AVQZ quality. For larger molecules, the additional cost for these improvements is only a few percent of the time for a standard CCSD(T) calculation. For the first time ever, total reaction energies with chemical accuracy are obtained using valence-double- basis sets.
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U2 - 10.1063/1.3054300
DO - 10.1063/1.3054300
M3 - Article
C2 - 19206955
AN - SCOPUS:59949093519
SN - 0021-9606
VL - 130
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 5
M1 - 054104
ER -