ISSN:
0020-7608
Keywords:
HeH-
;
comparative study of errors
;
SCF
;
electron correlation
;
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Basis set truncation error (BSTE), size extensivity Error (SEE), zero point vibrational energy (ZPVE), and basis set superposition error (BSSE) of HeH- weak van der Waals interaction energy were determined and compared at the self-consistent field (SCF), many-body perturbation theory (MBPT), and coupled cluster (CC) methods using even-tempered functions. Isotope substitution effects and the role of bond function augmentation were taken into account. Apart from core correlation energy error (CCEE), which is absent from HeH- interaction energy, the results confirm that BSTE is the most important source of error, followed by SEE of the truncated configuration interaction (CI) expansion, ZPVE and BSSE in a descending order. Introducing quadrable excitations to the truncated CI expansion reduces the magnitude of SEE by ∼45.7%, and BSSE correction is not necessary even at the electron correlation level. While bond function augmentation reduces BSSE at the Hartree-Fock, it has an oscillating behavior at the electron correlation level. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 68: 329-350, 1998
Additional Material:
10 Tab.
Type of Medium:
Electronic Resource
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