The Convergence of CASSCF Energies to the Complete Basis Set Limit
WESLEYAN UNIV MIDDLETOWN CT HALL-ATWATER LABS
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Examination of the convergence of full valence CASSCF energies with expansion of the one-electron basis set reveals a pattern very similar to the convergence of single determinant Hartree-Fock energies. Calculations on twenty-six molecular examples with the sequence of ntuple-sigma augmented polarized nZaP basis sets n 2, 3, 4, 5, and 6 are used to evaluate complete basis set CBS extrapolation schemes. The most effective extrapolation reduces the RMS one-electron basis set truncation errors from 3.03, 0.58, and 0.12 millihartree to 0.23, 0.05, and 0.014 millihartree for the 3ZaP, 4ZaP, and 5ZaP basis sets, respectively.
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy