title: Benchmarking for perturbative triple-excitations in EE-EOM-CC methods.
abstract: Perturbative triples corrections ((T) and (T̃)) to the equation of motion coupled cluster singles and doubles (EOM-CCSD) are rederived and implemented in a pilot parallel code. The vertical excitation energies of molecules in the test set of Sauer et al. [J. Chem. Theor. Comput. 2009, 5, 555] are reported and compared to the iterative EOM-CCSDT-3 method. The average absolute deviations of EOM-CCSD(T) and EOM-CCSD(T̃) from EOM-CCSDT-3 over this wide test set are 0.06 and 0.18 eV, respectively. The poor performance of the latter suggests misbalanced handling of the (T̃) terms. Scaling curves for EOM-CCSD(T) are also presented to demonstrate the performance across multiple compute nodes, thus enabling the routine and accurate study of excited states for ever larger molecular systems.
authors: Quantum Theory Project, Department of Chemistry and of Physics, University of Florida, P.O. Box 118435, Gainesville, Florida 32611-8435, USA. watson@qtp.ufl.edu
authors: Thomas J
authors: TJ
authors: Watson
authors: Victor F
authors: VF
authors: Lotrich
authors: Peter G
authors: PG
authors: Szalay
authors: Ajith
authors: A
authors: Perera
authors: Rodney J
authors: RJ
authors: Bartlett
mesh_terms: D000225:Adenine / Q000737:chemistry*; D019985:Benchmarking; D003596:Cytosine / Q000737:chemistry*; D004583:Electrons; D006147:Guanine / Q000737:chemistry*; D011789:Quantum Theory; D013816:Thermodynamics; D013941:Thymine / Q000737:chemistry*
chemical_list: D006147:Guanine; D003596:Cytosine; D000225:Adenine; D013941:Thymine