Application of unitary group methods to configuration interaction calculations

1979/12/01 by Dermot Hegarty, Michael A. Robb · 453 citations
Computer Science · Mathematics · Physics and Astronomy · #Algorithm #Computer science #Configuration interaction #Electromagnetic Scattering and Analysis #Excitation #Generator (circuit theory) #Group (periodic table) #Mathematics #Matrix Theory and Algorithms #Physics #Quantum mechanics #Scientific Research and Discoveries #Simple (philosophy) #Unitary group #Unitary matrix #Unitary state #Unitary transformation

paper · doi:10.1080/00268977900102871

published in Molecular Physics 38(6), 1795-1812 (Taylor & Francis)

openalex publication_date 1979/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29

Abstract

A computational approach to the direct configuration interaction method is described. The method is formulated using the calculus of the generators of the unitary group. The simple structure of the generator matrices within the harmonic excitation level scheme is exploited to give a computational method that is competitive with traditional approaches. A new scheme for basis set truncation in the case of partial configuration interaction is devised employing orbital populations. It is also shown that the block structure of the generator matrices leads to the definition of a new order parameter for perturbation methods which is both effective and convenient.

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