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The multireference constant denominator perturbation theory for one‐particle systems and its application to the anharmonic oscillator
Author(s) -
Lan Zhida,
Cullen John M.
Publication year - 1990
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560370103
Subject(s) - anharmonicity , basis set , perturbation theory (quantum mechanics) , padé approximant , perturbation (astronomy) , basis (linear algebra) , harmonic oscillator , quantum mechanics , schrödinger equation , mathematics , physics , molecule , geometry
In this paper a multireference constant denominator perturbation theory ( CDPT ) is developed to reduce incomplete basis set errors arising when solving the Schrödinger equation with a finite basis set. The advantage of this method is that very few basis functions are needed, and all calculations if carried out to high enough order in the perturbation treatment effectively use a complete basis set. As a first step the theory has been restricted to one‐particle Hamiltonians and applied to the anharmonic oscillator to study the convergence properties. For perturbation calculations carried out to fifth order, results from Pade approximates show an improvement in accuracy of between one and three orders of magnitude.