Assessing the impact of nodal surface optimization in fixed-node diffusion Monte Carlo on non-covalent interactions
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2026
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| _version_ | 1866911568821747712 |
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| author | Nakano, Kousuke Shi, Benjamin X. Alfè, Dario Zen, Andrea |
| author_facet | Nakano, Kousuke Shi, Benjamin X. Alfè, Dario Zen, Andrea |
| contents | Diffusion quantum Monte Carlo (DMC) and coupled cluster theory [CCSD(T)] are widely-employed benchmark methods for noncovalent interactions (NCIs). However, recent studies have reported notable discrepancies across several hydrogen-bonded and dispersion-dominated systems, raising questions on the accuracy of the approximations underlying each approach. In DMC, the dominant error is expected to stem from the fixed-node approximation, where the nodal surface is typically taken from a single Slater determinant derived from a density functional theory or Hartree-Fock calculation. In this work, we assess the impact of nodal surface optimization on DMC predictions for 12 compounds spanning diverse NCIs, using a recently proposed antisymmetrized geminal power ansatz with natural orbitals. We find improved agreement with CCSD(T) for hydrogen-bonded systems, while having negligible effect for dispersion-dominated systems. These results provide a practical and computationally efficient route to resolving discrepancies in hydrogen-bonded interactions, while offering insight into the remaining differences in dispersion-dominated systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_04329 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Assessing the impact of nodal surface optimization in fixed-node diffusion Monte Carlo on non-covalent interactions Nakano, Kousuke Shi, Benjamin X. Alfè, Dario Zen, Andrea Chemical Physics Strongly Correlated Electrons Computational Physics Diffusion quantum Monte Carlo (DMC) and coupled cluster theory [CCSD(T)] are widely-employed benchmark methods for noncovalent interactions (NCIs). However, recent studies have reported notable discrepancies across several hydrogen-bonded and dispersion-dominated systems, raising questions on the accuracy of the approximations underlying each approach. In DMC, the dominant error is expected to stem from the fixed-node approximation, where the nodal surface is typically taken from a single Slater determinant derived from a density functional theory or Hartree-Fock calculation. In this work, we assess the impact of nodal surface optimization on DMC predictions for 12 compounds spanning diverse NCIs, using a recently proposed antisymmetrized geminal power ansatz with natural orbitals. We find improved agreement with CCSD(T) for hydrogen-bonded systems, while having negligible effect for dispersion-dominated systems. These results provide a practical and computationally efficient route to resolving discrepancies in hydrogen-bonded interactions, while offering insight into the remaining differences in dispersion-dominated systems. |
| title | Assessing the impact of nodal surface optimization in fixed-node diffusion Monte Carlo on non-covalent interactions |
| topic | Chemical Physics Strongly Correlated Electrons Computational Physics |
| url | https://arxiv.org/abs/2604.04329 |