Invariance properties of the moments of the hamiltonian matrix as a test of the correctness of configuration interaction programs
โ Scribed by Geerd H.F. Diercksen; Jacek Karwowski
- Publisher
- Elsevier Science
- Year
- 1987
- Tongue
- English
- Weight
- 530 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0010-4655
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โฆ Synopsis
An invariance of the spectrum of a full configuration interaction (CI) matrix with respect to unitary transformations of the orbital basis set is frequently used as a test of the correctness of CI programs. In this paper we argue that using instead the invariance properties of the first two moments of the spectrum of the matrix is both simpler and more conclusive. Explicit formulae for the moments are derived and their usefulness is illustrated by several examples.
๐ SIMILAR VOLUMES
The size consistency of selected multireference CI approaches is tested on two model problems, namely seven non-interacting H, molecules at their equilibrium bond length r, or at 2r, and seven non-interacting Ne atoms, In all cases the results obtained from the two-class CIPSI method (which is a mul