dorsal/arxiv
View SchemaClosed-form expressions for correlated density matrices: application to dispersive interactions and example of (He)2
| Authors | Sebastien Ragot, Pierre J. Becker |
|---|---|
| Categories | |
| ArXiv ID | physics/0606140 |
| URL | https://arxiv.org/abs/physics/0606140 |
| DOI | 10.1063/1.2358977 |
| Journal | J. Chem. Phys. 125, 154109 (2006) |
Abstract
Empirically correlated density matrices of N-electron systems are investigated. Exact closed-form expressions are derived for the one- and two-electron reduced density matrices from a general pairwise correlated wave function. Approximate expressions are proposed which reflect dispersive interactions between closed-shell centro-symmetric subsystems. Said expressions clearly illustrate the consequences of second-order correlation effects on the reduced density matrices. Application is made to a simple example: the (He)2 system. Reduced density matrices are explicitly calculated, correct to second order in correlation, and compared with approximations of independent electrons and independent electron pairs. The models proposed allow for variational calculations of interaction energies and equilibrium distance as well as a clear interpretation of dispersive effects on electron distributions. Both exchange and second order correlation effects are shown to play a critical role on the quality of the results.
{
"annotation_id": "4283e12d-49d7-43de-b6ae-ba7bb817f4c2",
"date_created": "2026-03-02T18:01:10.593000Z",
"date_modified": "2026-03-02T18:01:10.593000Z",
"file_hash": "d62206b40467998c8d8c1fffc14ce41bf41a08ebf1c8d704cd9a0b7a9b4b711b",
"private": false,
"record": {
"abstract": "Empirically correlated density matrices of N-electron systems are\ninvestigated. Exact closed-form expressions are derived for the one- and\ntwo-electron reduced density matrices from a general pairwise correlated wave\nfunction. Approximate expressions are proposed which reflect dispersive\ninteractions between closed-shell centro-symmetric subsystems. Said expressions\nclearly illustrate the consequences of second-order correlation effects on the\nreduced density matrices. Application is made to a simple example: the (He)2\nsystem. Reduced density matrices are explicitly calculated, correct to second\norder in correlation, and compared with approximations of independent electrons\nand independent electron pairs. The models proposed allow for variational\ncalculations of interaction energies and equilibrium distance as well as a\nclear interpretation of dispersive effects on electron distributions. Both\nexchange and second order correlation effects are shown to play a critical role\non the quality of the results.",
"arxiv_id": "physics/0606140",
"authors": [
"Sebastien Ragot",
"Pierre J. Becker"
],
"categories": [
"physics.chem-ph",
"physics.class-ph"
],
"doi": "10.1063/1.2358977",
"journal_ref": "J. Chem. Phys. 125, 154109 (2006)",
"title": "Closed-form expressions for correlated density matrices: application to dispersive interactions and example of (He)2",
"url": "https://arxiv.org/abs/physics/0606140"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "a39767ac-3ced-444b-9ac0-f989931f5fd4",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}