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A Note on the Quantum-Mechanical Perturbation Theory

Löwdin, Per-Olov·1951·The Journal of Chemical Physics

Abstract

The solution of the quantum-mechanical eigenvalue problem is discussed for cases when a series of approximate eigenfunctions is known. If these ``unperturbed'' states are divided into two classes, a perturbation formula is derived giving the influence of one class of states on the other in the final solution. The formula contains as special cases: (i) the Schrödinger-Brillouin formula for the eigenvalue of a nondegenerate state, (ii) a new simple formula for treating a class of degenerate states, and (iii) the splitting of the secular equation in cases where the system naturally consists of two independent parts in mutual interaction.

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Metadata

Authors
Löwdin, P.-O.
Venue
The Journal of Chemical Physics
Published
1951-11-01
Volume
19
Issue
11
Pages
1396-1401
ISSN
  • 0021-9606 (ISSN-L)
  • 1089-7690
OpenAlex
W2116008596
Cited by
944
References
0
FWCI
2.92
Type
journal article
Language
en
Open access
closed

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CoChat. (2026). Citation check: A Note on the Quantum-Mechanical Perturbation Theory. https://app.cochat.ai/papers/10.1063/1.1748067
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Löwdin, P.-O. (1951). A Note on the Quantum-Mechanical Perturbation Theory. The Journal of Chemical Physics. https://doi.org/10.1063/1.1748067

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Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).

Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.