## Abstract A new perturbation approach is proposed that enhances the low‐order, perturbative convergence by modifying the zeroth‐order Hamiltonian in a manner that enlarges any small‐energy denominators that may otherwise appear in the perturbative expansion. This intruder state avoidance (ISA) me
Multireference Møller—Plesset perturbation theory for high-spin open-shell systems
✍ Scribed by K. Hirao
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 601 KB
- Volume
- 196
- Category
- Article
- ISSN
- 0009-2614
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📜 SIMILAR VOLUMES
Single-reference closed-shell Møller᎐Plesset perturbation theory is well known for its size consistency, a quality that is essential for consistent comparisons of calculations on molecules of different size. However, it is far from obvious whether this quality can be retained in the multireference c
A theory for the evaluation of the gradient ofthe second-order restricted open-shell Meller-Plesset (RMP) energy is presented. It is not straightfonvard because the use of semi-canonical orbitals forms an essential part of RMP theory. Stationary conditions which determine the semi-canonical orbitals