Accurate correlation consistent basis sets for molecular core-valence correlation effects: The second row atoms Al-Ar and the first row atoms B-Ne revisited

Journal Article · Sun Dec 15 04:00:00 EST 2002 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.1520138· OSTI ID:15002637

Peterson, Kirk A ^[1]; Dunning, Thom H ^[2]

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1. WASHINGTON STATE UNIV TC
2. BATTELLE (PACIFIC NW LAB)

Correlation consistent basis sets for accurately describing core-core and core-valence correlation effects in atoms and molecules have been developed for the second row atoms Al - Ar. Two different optimization strategies were investigated, which led to two families of core-valence basis sets when the optimized functions were added to the standard correlation consistent basis sets (cc-pVnZ). In the first case, the exponents of the augmenting primitive Gaussian functions were optimized with respect to the difference between all-electron and valence-electron correlated calculations, i.e., for the core-core plus core-valence correlation energy. This yielded the cc-pCVnZ family of basis sets, which are analogous to the sets developed previously for the first row atoms[D.E. Woon and T.H. Dunning, Jr., J. Chem. Phys. 103, 4572 (1995)]. Although the cc-pCVnZ sets exhibit systematic convergence to the all-electron correlation energy at the complete basis set limit, the intershell (core-valence ) correlation energy converges more slowly than the intrashell (core-core) correlation energy. Since the effect of including the core electrons on the calculation of molecular properties tends to be dominated by core-valence correlation effects, a second scheme for determining the augmenting functions was investigated. In this approach, the exponents of the functions to be added to the cc-pVnZ sets were optimized with respect to just the core-valence (intershell) correlation energy, except that a small amount of core-core correlation energy was included in order to ensure systematic convergence to the complete basis set limit. These new sets, denoted weighted core-valence basis sets (cc-pwCVnZ), significantly improve the convergence of many molecular properties with n. Optimum cc-pwCVnZ sets for the first-row atoms were also developed and show similar advantages.

• Research Organization: Pacific Northwest National Lab., Richland, WA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 15002637
• Report Number(s): PNNL-SA-36477; KC0301020
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 23 Vol. 117; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALUMINIUM
ARGON
BORON
CARBON
CHLORINE
ELECTRON CORRELATION
FLUORINE
NEON
NITROGEN
OXYGEN
PHOSPHORUS
SILICON
SULFUR
VALENCE