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Degenerate RS perturbation theoryA concise, systematic procedure is given for determining the Rayleigh-Schroedinger energies and wave functions of degenerate states to arbitrarily high orders even when the degeneracies of the various states are resolved in arbitrary orders. The procedure is expressed in terms of an iterative cycle in which the energy through the (2n + 1)-th order is expressed in terms of the partially determined wave function through the n-th order. Both a direct and an operator derivation are given. The two approaches are equivalent and can be transcribed into each other. The direct approach deals with the wave functions (without the use of formal operators) and has the advantage that it resembles the usual treatment of nondegenerate perturbations and maintains close contact with the basic physics. In the operator approach, the wave functions are expressed in terms of infinite-order operators which are determined by the successive resolution of the space of the zeroth-order functions.
Document ID
19740041796
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Hirschfelder, J. O.
Certain, P. R. (Wisconsin, University Madison, Wis., United States)
Date Acquired
August 7, 2013
Publication Date
February 1, 1974
Publication Information
Publication: Journal of Chemical Physics
Volume: 60
Subject Category
PHYSICS, GENERAL
Funding Number(s)
CONTRACT_GRANT: NSF GP-28213A1
CONTRACT_GRANT: DA-ARO(D)-31-G179
CONTRACT_GRANT: NGL-50-002-001
Distribution Limits
Public
Copyright
Other