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
- WASHINGTON STATE UNIV TC
- 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; JCPSA6; KC0301020; TRN: US200416%%164
- Journal Information:
- Journal of Chemical Physics, Vol. 117, Issue 23; Other Information: PBD: 15 Dec 2002; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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