Coupled-cluster based basis sets for valence correlation calculations

• Published in: The Journal of chemical physics Vol. 144; no. 10; pp. 104106 - 104116
• Main Authors: Claudino, Daniel, Gargano, Ricardo, Bartlett, Rodney J.
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics 14.03.2016
• Subjects: ATOMIC AND MOLECULAR PHYSICS; Atomic properties; CALCULATION METHODS; Clusters; COMPUTER CALCULATIONS; CONTRACTION; Correlation; Curve fitting; Density; DENSITY MATRIX; Diatomic molecules; ELECTRON CORRELATION; Energy measurement; GAUSS FUNCTION; Mathematical analysis; Organic chemistry; Physics; POTENTIAL ENERGY; Theorems; VALENCE; Virial theorem
• ISSN: 0021-9606; 1089-7690; 1089-7690
• DOI: 10.1063/1.4943275

Novel basis sets are generated that target the description of valence correlation in atoms H through Ar. The new contraction coefficients are obtained according to the Atomic Natural Orbital (ANO) procedure from CCSD(T) (coupled-cluster singles and doubles with perturbative triples correction) density matrices starting from the primitive functions of Dunning et al. [J. Chem. Phys. 90, 1007 (1989); ibid. 98, 1358 (1993); ibid. 100, 2975 (1993)] (correlation consistent polarized valence X-tuple zeta, cc-pVXZ). The exponents of the primitive Gaussian functions are subject to uniform scaling in order to ensure satisfaction of the virial theorem for the corresponding atoms. These new sets, named ANO-VT-XZ (Atomic Natural Orbital Virial Theorem X-tuple Zeta), have the same number of contracted functions as their cc-pVXZ counterparts in each subshell. The performance of these basis sets is assessed by the evaluation of the contraction errors in four distinct computations: correlation energies in atoms, probing the density in different regions of space via 〈rn 〉 (−3 ≤ n ≤ 3) in atoms, correlation energies in diatomic molecules, and the quality of fitting potential energy curves as measured by spectroscopic constants. All energy calculations with ANO-VT-QZ have contraction errors within “chemical accuracy” of 1 kcal/mol, which is not true for cc-pVQZ, suggesting some improvement compared to the correlation consistent series of Dunning and co-workers.