Numerical examples are presented to demonstrate that the biorthogonal formulation of exchange perturbation theory, in contrast with common belief, does not run into difficulties when significant overlap occurs. Previously observed instabilities can be attributed to an improper partitioning of the hamiltonian, which, however, is commonly used in perturbation theories for intermolecular interactions.
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry