Variants of Rayleigh–Schrödinger perturbation theory—a new look

✍ Scribed by Kamal Bhattacharyya

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 648 KB
• Volume: 20
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/qua.560200611

✦ Synopsis

Abstract

Several useful “redefined zero‐order Hamiltonian” variants of the Rayleigh–Schrödinger perturbation theory are derived by exploiting the freedom of choice for the orthogonality integral between zero‐ and first‐order wavefunctions. It is found that the more common Hamiltonian repartitioning schemes follow quite naturally, as a consequence of certain consistency requirements. The strategy adopted may as well be employed to derive various newer and profitable zero‐order Hamiltonians depending on the nature of the problems. This implication is strengthened by demonstrating the calculational success of one such derived scheme. Feenberg's “scale‐changed” Hamiltonian approach is also reinterpreted in the present context.