FNO-CCSDTQ(5)$_Λ$ as an economical alternative for connected quintuple excitations contributions in coupled cluster thermochemistry
Fuente:
arXiv
Enregistré dans:
| Auteurs principaux: | , , , |
|---|---|
| Format: | Preprint |
| Publié: |
2026
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866913151922995200 |
|---|---|
| author | Jones, Gregory H. Barman, Aditya Shepelenko, Margarita Martin, Jan M. L. |
| author_facet | Jones, Gregory H. Barman, Aditya Shepelenko, Margarita Martin, Jan M. L. |
| contents | Contributions from connected quintuple excitations in coupled cluster theory can reach the 0.5 kcal/mol range, important enough to matter in accurate computational thermochemistry, yet the very steep $\propto N^{12}$ CPU time scaling impedes routine evaluation. We show that for the differential contribution of quintuples, convergence of a frozen natural orbital (FNO) expansion with respect to the NO cutoff is rapid enough to make FNO-CCSDTQ(5)$_Λ$ with cutoffs of 0.0025 or 0.001 viable alternatives. A naive extrapolation to zero cutoff from \{0.005,0.0025\} works surprisingly well as a low-cost option. Interestingly, FNO convergence is definitely slower for second-row than for first-row compounds. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_19874 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | FNO-CCSDTQ(5)$_Λ$ as an economical alternative for connected quintuple excitations contributions in coupled cluster thermochemistry Jones, Gregory H. Barman, Aditya Shepelenko, Margarita Martin, Jan M. L. Chemical Physics Contributions from connected quintuple excitations in coupled cluster theory can reach the 0.5 kcal/mol range, important enough to matter in accurate computational thermochemistry, yet the very steep $\propto N^{12}$ CPU time scaling impedes routine evaluation. We show that for the differential contribution of quintuples, convergence of a frozen natural orbital (FNO) expansion with respect to the NO cutoff is rapid enough to make FNO-CCSDTQ(5)$_Λ$ with cutoffs of 0.0025 or 0.001 viable alternatives. A naive extrapolation to zero cutoff from \{0.005,0.0025\} works surprisingly well as a low-cost option. Interestingly, FNO convergence is definitely slower for second-row than for first-row compounds. |
| title | FNO-CCSDTQ(5)$_Λ$ as an economical alternative for connected quintuple excitations contributions in coupled cluster thermochemistry |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2605.19874 |