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Accelerating convergence to the thermodynamic limit with twist angle selection applied to methods beyond many-body perturbation theory
Journal article   Peer reviewed

Accelerating convergence to the thermodynamic limit with twist angle selection applied to methods beyond many-body perturbation theory

Tina N Mihm, William Z Van Benschoten and James J Shepherd
The Journal of chemical physics, Vol.154(2), pp.024113-024113
11/16/2020
DOI: 10.1063/5.0033408
PMID: 33445909
url
https://arxiv.org/pdf/2011.08113View
Open Access

Abstract

We recently developed a scheme to use low-cost calculations to find a single twist angle where the couple cluster doubles energy of a single calculation matches the twist-averaged coupled cluster doubles energy in a finite unit cell. We used initiator full configuration interaction quantum Monte Carlo ($i$-FCIQMC) as an example of an exact method beyond coupled cluster doubles theory to show that this selected twist angle approach had comparable accuracy in methods beyond coupled cluster. Further, at least for small system sizes, we show that the same twist angle can also be found by comparing the energy directly (at the level of second-order Moller-Plesset theory) suggesting a route toward twist angle selection which requires minimal modification to existing codes which can perform twist averaging.

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