Accelerating the Convergence of Higher-Order Coupled Cluster Methods II: Coupled Cluster $Λ$ Equations and Dynamic Damping
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arXiv
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| Format: | Preprint |
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2020
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| _version_ | 1866916660982579200 |
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| author | Matthews, Devin A. |
| author_facet | Matthews, Devin A. |
| contents | The method of sub-iteration, which was previously applied to the higher-order coupled cluster amplitude equations, is extended to the case of the coupled cluster $Λ$ equations. The sub-iteration procedure for the $Λ$ equations is found to be highly similar to that for the amplitude equations, and to exhibit a similar improvement in rate of convergence relative to extrapolation of all $\hat{T}$ or $\hatΛ$ amplitudes using DIIS. A method of dynamic damping is also presented which is found to effectively recover rapid convergence in the case of oscillatory behavior in the amplitude or $Λ$ equations. Together, these techniques allow for the convergence of both the amplitude and $Λ$ equations necessary for the calculation of analytic gradients and properties of higher-order coupled cluster methods without the high memory or disk I/O cost of full DIIS extrapolation. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2003_03455 |
| institution | arXiv |
| publishDate | 2020 |
| record_format | arxiv |
| spellingShingle | Accelerating the Convergence of Higher-Order Coupled Cluster Methods II: Coupled Cluster $Λ$ Equations and Dynamic Damping Matthews, Devin A. Chemical Physics The method of sub-iteration, which was previously applied to the higher-order coupled cluster amplitude equations, is extended to the case of the coupled cluster $Λ$ equations. The sub-iteration procedure for the $Λ$ equations is found to be highly similar to that for the amplitude equations, and to exhibit a similar improvement in rate of convergence relative to extrapolation of all $\hat{T}$ or $\hatΛ$ amplitudes using DIIS. A method of dynamic damping is also presented which is found to effectively recover rapid convergence in the case of oscillatory behavior in the amplitude or $Λ$ equations. Together, these techniques allow for the convergence of both the amplitude and $Λ$ equations necessary for the calculation of analytic gradients and properties of higher-order coupled cluster methods without the high memory or disk I/O cost of full DIIS extrapolation. |
| title | Accelerating the Convergence of Higher-Order Coupled Cluster Methods II: Coupled Cluster $Λ$ Equations and Dynamic Damping |
| topic | Chemical Physics |
| url | https://arxiv.org/abs/2003.03455 |