A1 - Cardoem Wim
A2 - Gdanitz Robert J.
PB - OWN
N2 - We investigate the performance of two approaches to remedy the notorious instability problems on explicitly correlated multi-reference averaged coupled-pair functional (r12-MR-ACPF) level of theory for the cases of HF molecule and Ne dimer. These two approaches are: i) the restriction of the unitary orbital invariance while retaining a chemically meaningful ansatz; ii) the contraction of associated r12-terms to geminals using amplitudes from the first-order perturbation theory wavefunction. We observe that our modifications outperform the extremal pair approach, which is commonly used on explicitly correlated coupled-cluster (CC-R12) level of theory and conclude that using geminals, which are e.g. taken from the first-order Mřller-Plesset perturbation theory wavefunction instead, might be a better choice.
L1 - http://lib.psnc.pl/Content/550/10.12921_cmst.2003.09.01.31-43_Cardoen.pdf
L2 - http://lib.psnc.pl/Content/550
CY - Poznań
ER -
UR - http://lib.psnc.pl/dlibra/docmetadata?id=550