dorsal/arxiv
View SchemaFourth-order perturbative extension of the singles-doubles coupled-cluster method
| Authors | Andrei Derevianko, Erik D. Emmons |
|---|---|
| Categories | |
| ArXiv ID | physics/0204056 |
| URL | https://arxiv.org/abs/physics/0204056 |
| DOI | 10.1103/PhysRevA.66.012503 |
Abstract
Fourth-order many-body corrections to matrix elements for atoms with one valence electron are derived. The obtained diagrams are classified using coupled-cluster-inspired separation into contributions from n-particle excitations from the lowest-order wavefunction. The complete set of fourth-order diagrams involves only connected single, double, and triple excitations and disconnected quadruple excitations. Approximately half of the fourth-order diagrams are not accounted for by the popular coupled-cluster method truncated at single and double excitations (CCSD). Explicit formulae are tabulated for the entire set of fourth-order diagrams missed by the CCSD method and its linearized version, i.e. contributions from connected triple and disconnected quadruple excitations. A partial summation scheme of the derived fourth-order contributions to all orders of perturbation theory is proposed.
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"date_created": "2026-03-02T18:00:39.425000Z",
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"abstract": "Fourth-order many-body corrections to matrix elements for atoms with one\nvalence electron are derived. The obtained diagrams are classified using\ncoupled-cluster-inspired separation into contributions from n-particle\nexcitations from the lowest-order wavefunction. The complete set of\nfourth-order diagrams involves only connected single, double, and triple\nexcitations and disconnected quadruple excitations. Approximately half of the\nfourth-order diagrams are not accounted for by the popular coupled-cluster\nmethod truncated at single and double excitations (CCSD). Explicit formulae are\ntabulated for the entire set of fourth-order diagrams missed by the CCSD method\nand its linearized version, i.e. contributions from connected triple and\ndisconnected quadruple excitations. A partial summation scheme of the derived\nfourth-order contributions to all orders of perturbation theory is proposed.",
"arxiv_id": "physics/0204056",
"authors": [
"Andrei Derevianko",
"Erik D. Emmons"
],
"categories": [
"physics.atom-ph"
],
"doi": "10.1103/PhysRevA.66.012503",
"title": "Fourth-order perturbative extension of the singles-doubles coupled-cluster method",
"url": "https://arxiv.org/abs/physics/0204056"
},
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