Repartitioning the Hamiltonian in many-body second-order Brillouin-Wigner perturbation theory: uncovering new size-consistent models
Second-order Møller-Plesset perturbation theory is well-known as a computationally inexpensive approach to the electron correlation problem that is size-consistent with a size-consistent reference but fails to be regular. On the other hand, the less well-known many-body version of Brillouin-Wigner p...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
7 February 2025
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| In: |
The journal of chemical physics
Year: 2025, Volume: 162, Issue: 5, Pages: 1-16 |
| ISSN: | 1089-7690 |
| DOI: | 10.1063/5.0242211 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1063/5.0242211
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| Author Notes: | Linus Bjarne Dittmer and Martin Head-Gordon |
| Summary: | Second-order Møller-Plesset perturbation theory is well-known as a computationally inexpensive approach to the electron correlation problem that is size-consistent with a size-consistent reference but fails to be regular. On the other hand, the less well-known many-body version of Brillouin-Wigner perturbation theory has the reverse properties: it is regular but fails to be size-consistent when used with the standard MP partitioning. Consequently, its widespread use remains limited. In this work, we analyze the ways in which it is possible to use alternative non-MP partitions of the Hamiltonian to yield variants of BW2 that are size-consistent as well as regular. We show that there is a vast space of such BW2 theories and also show that it is possible to define a repartitioned BW2 theory from the ground state density alone, which regenerates the exact correlation energy. We also provide a general recipe for deriving regular, size-consistent, and size-extensive partitions from physically meaningful components, and we apply the result to small model systems. The scope of these results appears to further set the stage for a revival of BW2 in quantum chemistry. |
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| Item Description: | Online verfügbar: 4. Februar 2025 Gesehen am 28.07.2025 |
| Physical Description: | Online Resource |
| ISSN: | 1089-7690 |
| DOI: | 10.1063/5.0242211 |