The content discusses the finite-size error scaling in periodic coupled cluster theory for three-dimensional insulating systems. Key points:
Finite-size errors can significantly affect the accuracy of quantum chemistry calculations, even for systems with thousands of atoms. Understanding the finite-size scaling and employing correction schemes are crucial.
Previous studies have shown that the finite-size error in Hartree-Fock and MP2 calculations exhibits inverse volume scaling, but the scaling in coupled cluster (CC) theory remained unclear.
The authors analyze the finite-size error in coupled cluster doubles (CCD) theory, which is the simplest form of CC theory. They decompose the finite-size error into errors in three basic components: energy calculation using exact amplitudes, electron repulsion integral (ERI) contractions using exact amplitudes, and orbital energies.
The authors show that the Madelung constant correction can reduce the finite-size errors in both orbital energies and ERI contractions from the inverse length scaling to the inverse volume scaling.
When the Madelung constant correction is applied to both orbital energies and ERI contractions, the overall finite-size error in CCD(n) and converged CCD calculations scales as inverse volume.
The authors provide rigorous mathematical analysis and numerical validation to support their findings, reconciling the seemingly paradoxical observations about the finite-size error scaling in coupled cluster theory.
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by Xin Xing,Lin... at arxiv.org 04-02-2024
https://arxiv.org/pdf/2304.03330.pdfDeeper Inquiries