State-selective multi-reference coupled-cluster theory using multi-configuration self-consistent-field orbitals. A model study on H8
✍ Scribed by Piotr Piecuch; Ludwik Adamowicz
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 729 KB
- Volume
- 221
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
✦ Synopsis
The recently developed state-selective (SS) multi-reference (MR) coupled-cluster (CC) method is applied to a prototype molecular system composed of eight hydrogen atoms. To obtain a better description of the zeroth-order wavefunction in the quasidegenerate region, we employ orbitals resulting from the complete active space multi-configurational self-consistent-field (MC SCF) optimization. Comparison with the results obtained using the ground-state restricted Hartree-Fock SCF orbitals indicates invariant character of the SS CC theory with respect to the orbital choice, contrary to the behavior of the Hilbert-space state-universal MR CC method.