W4$Λ$: leveraging $Λ$ coupled cluster for accurate computational thermochemistry approaches
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arXiv
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| Format: | Preprint |
| Publié: |
2023
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| _version_ | 1866916200597946368 |
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| author | Semidalas, Emmanouil Karton, Amir Martin, Jan M. L. |
| author_facet | Semidalas, Emmanouil Karton, Amir Martin, Jan M. L. |
| contents | High-accuracy composite wavefunction methods like Weizmann-4 (W4) theory, high-accuracy extrapolated \textit{ab initio} thermochemistry (HEAT), and Feller-Peterson-Dixon (FPD) enable sub-kJ/mol accuracy in gas-phase thermochemical properties. Their biggest computational bottleneck is the evaluation of the valence post-CCSD(T) correction term. We demonstrate here, for the W4-17 thermochemistry benchmark and subsets thereof, that the lambda coupled cluster expansion converges more rapidly and smoothly than the regular coupled cluster series. By means of CCSDT(Q)$_Λ$ and CCSDTQ(5)$_Λ$, we can considerably (up to an order of magnitude) accelerate W4- and W4.3-type calculations without loss in accuracy, leading to the W4$Λ$ and W4.3$Λ$ computational thermochemistry protocols. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2312_09062 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | W4$Λ$: leveraging $Λ$ coupled cluster for accurate computational thermochemistry approaches Semidalas, Emmanouil Karton, Amir Martin, Jan M. L. Chemical Physics High-accuracy composite wavefunction methods like Weizmann-4 (W4) theory, high-accuracy extrapolated \textit{ab initio} thermochemistry (HEAT), and Feller-Peterson-Dixon (FPD) enable sub-kJ/mol accuracy in gas-phase thermochemical properties. Their biggest computational bottleneck is the evaluation of the valence post-CCSD(T) correction term. We demonstrate here, for the W4-17 thermochemistry benchmark and subsets thereof, that the lambda coupled cluster expansion converges more rapidly and smoothly than the regular coupled cluster series. By means of CCSDT(Q)$_Λ$ and CCSDTQ(5)$_Λ$, we can considerably (up to an order of magnitude) accelerate W4- and W4.3-type calculations without loss in accuracy, leading to the W4$Λ$ and W4.3$Λ$ computational thermochemistry protocols. |
| title | W4$Λ$: leveraging $Λ$ coupled cluster for accurate computational thermochemistry approaches |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2312.09062 |