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Seniority-zero wavefunction parameterizations

delete2025-11-04
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PRE
AI
D
Daniel F. Calero-Osorio *
P
Paul W. Ayers
DOI:10.1007/s00214-025-03245-xdelete
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Abstract

Abstract

En 中文
Wave function methods tailored to seniority-zero Hamiltonians have emerged as practical tools for describing strong (static) electron correlation while retaining computational tractability. The seniority quantum number counts unpaired electrons; setting it to zero restricts the wave function to doubly occupied or empty spatial orbitals, yielding geminal-based ans & auml;tze and a Hilbert space that scales as the square root of the full configuration space. This structure enables inexpensive evaluation of reduced density matrices-up to fourth order-facilitating post-geminal treatments of dynamic correlation. We review the main families of seniority-zero (pair-preserving) wave functions, from the antisymmetric product of geminals (APG) and its interacting (APIG) and strongly orthogonal (APSG) reductions, through generalized valence bond/perfect pairing (GVB-PP), to modern mean-field-cost approaches such as AP1roG (equivalent to pair coupled cluster). For each, we summarize formal properties (size consistency/extensivity), computational scaling, typical accuracy, and common add-ons for recovering missing dynamic correlation (perturbation theory, density functionals, multireference coupled cluster). We close by outlining opportunities for future development.
Keywords:
Seniority-zero
Geminals
Reduced density matrices
Electronic correlation

Journal

Theoretical Chemistry Accounts cover
Theoretical Chemistry Accounts
IF:
1.5
Papers:
96
Citations:
7.1K

Organization

M
mcmaster university
Scholars:
5.6K
Papers: 2.3K
Citations: 0