Abstract
We study the adiabatic connection that has as weak-coupling expansion the Møller-Plesset perturbation series, generalizing to the open-shell case previous closed-shell results for the large-coupling limit. We first focus on the hydrogen atom with fractional spins, providing results along the adiabatic connection from small to large coupling strengths. We reveal an intriguing phase diagram and an equation for the large-coupling leading order that has closed-form solutions for specific choices of its relevant quantum numbers. We then show that the hydrogen atom results provide variational estimates for the large-coupling leading terms for the general many-electron open-shell case in terms of functionals of the Hartree-Fock α-spin and β-spin densities.
| Original language | English |
|---|---|
| Pages (from-to) | 4138-4149 |
| Number of pages | 12 |
| Journal | Journal of Physical Chemistry A |
| Volume | 128 |
| Issue number | 20 |
| Early online date | 8 May 2024 |
| DOIs | |
| Publication status | Published - 23 May 2024 |
Bibliographical note
Publisher Copyright:© 2024 The Authors. Published by American Chemical Society.
Funding
It is a pleasure to dedicate this paper to Gustavo Scuseria, whose deep work and understanding of strong correlation in many-electron systems have been a continuous source of inspiration. We also want to thank Klaas Giesbertz for his suggestions. Financial support from The Netherlands Organisation for Scientific Research (NWO) under Vici grant 724.017.001 is acknowledged.
| Funders | Funder number |
|---|---|
| Nederlandse Organisatie voor Wetenschappelijk Onderzoek | 724.017.001 |
| Nederlandse Organisatie voor Wetenschappelijk Onderzoek |