Convergence of the Interaction Energies in Noncovalent
Complexes in the Coupled-Cluster Methods Up to Full Configuration
Interaction
Lucia Šimová
Jan Řezáč
Pavel Hobza
10.1021/ct4002762.s001
https://acs.figshare.com/articles/journal_contribution/Convergence_of_the_Interaction_Energies_in_Noncovalent_Complexes_in_the_Coupled_Cluster_Methods_Up_to_Full_Configuration_Interaction/2387974
The CCSD(T) method stands out among
various coupled-cluster (CC)
approximations as the “golden standard” in computational
chemistry and is widely and successfully used in the realm of covalent
and noncovalent interactions. The CCSD(T) method provides reliable
interaction energies, but their surprising accuracy is believed to
arise partially from an error compensation. The convergence of the
CC expansion has been investigated up to fully iterative pentuple
excitations (CCSDTQP); for the smallest eight electron complexes,
the full CI calculations have also been performed. We conclude that
the convergence of interaction energy at noncovalent accuracy (0.01
kcal/mol) for the complexes studied is reached already at CCSDTQ or
CCSDT(Q) levels. When even higher accuracy (spectroscopic accuracy
of 1 cm<sup>–1</sup>, or 3 cal/mol) is required, then the noniterative
CCSDTQ(P) method could
be used.
2013-08-13 00:00:00
CI calculations
iterative pentuple excitations
noncovalent interactions
CCSD
error compensation
interaction energy
spectroscopic accuracy
method
Noncovalent Complexes
interaction energies
Interaction Energies
convergence
electron complexes
CCSDTQ
CCSDTQP
CC expansion
CCSDT