Open-shell Tensor Hypercontraction
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arXiv
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| Autores principales: | , , |
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| Formato: | Preprint |
| Publicado: |
2023
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| _version_ | 1866908281591562240 |
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| author | Zhao, Tingting Simons, Megan Matthews, Devin A. |
| author_facet | Zhao, Tingting Simons, Megan Matthews, Devin A. |
| contents | The extension of least-squares tensor hypercontracted second- and third-order Møller-Plessett perturbation theory (LS-THC-MP2 and LS-THC-MP3) to open-shell systems is an important development due to the scaling reduction afforded by THC and the ubiquity of molecular ions, radicals, and other open-shell reactive species. The complexity of wavefunction-based quantum chemical methods such as Møller-Plessett and coupled cluster theory is reflected in the steep scaling of the computational costs with the molecular size. The least-squares tensor hypercontraction (LS-THC) method is an efficient, single-step factorization for the two-electron integral tensor, but can also be used to factorize the double excitation amplitudes, leading to significant scaling reduction. Here, we extend this promising method to open-shell variants of LS-THC-MP2 and -MP3 using diagrammatic techniques and explicit spin-summation. The accuracy of the resulting methods for open-shell species is benchmarked on standard tests systems such as regular alkanes, as well as realistic systems involving bond breaking, radical stabilization, and other effects. We find that open-shell LS-THC-MP$n$ methods exhibit errors highly comparable to those produced by closed-shell LS-THC-MP$n$, and are highly insensitive to particular chemical interactions, geometries, or even to moderate spin contamination. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2304_04040 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Open-shell Tensor Hypercontraction Zhao, Tingting Simons, Megan Matthews, Devin A. Chemical Physics The extension of least-squares tensor hypercontracted second- and third-order Møller-Plessett perturbation theory (LS-THC-MP2 and LS-THC-MP3) to open-shell systems is an important development due to the scaling reduction afforded by THC and the ubiquity of molecular ions, radicals, and other open-shell reactive species. The complexity of wavefunction-based quantum chemical methods such as Møller-Plessett and coupled cluster theory is reflected in the steep scaling of the computational costs with the molecular size. The least-squares tensor hypercontraction (LS-THC) method is an efficient, single-step factorization for the two-electron integral tensor, but can also be used to factorize the double excitation amplitudes, leading to significant scaling reduction. Here, we extend this promising method to open-shell variants of LS-THC-MP2 and -MP3 using diagrammatic techniques and explicit spin-summation. The accuracy of the resulting methods for open-shell species is benchmarked on standard tests systems such as regular alkanes, as well as realistic systems involving bond breaking, radical stabilization, and other effects. We find that open-shell LS-THC-MP$n$ methods exhibit errors highly comparable to those produced by closed-shell LS-THC-MP$n$, and are highly insensitive to particular chemical interactions, geometries, or even to moderate spin contamination. |
| title | Open-shell Tensor Hypercontraction |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2304.04040 |