Natural Orbitals for Wave Function Based Correlated Calculations Using a Plane Wave Basis Set

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• 作者：Andreas Gru虉neis ; George H. Booth ; Martijn Marsman ; James Spencer ; Ali Alavi ; Georg Kresse
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2011
• 出版时间：September 13, 2011
• 年：2011
• 卷：7
• 期：9
• 页码：2780-2785
• 全文大小：772K
• 年卷期：v.7,no.9(September 13, 2011)
• ISSN：1549-9626

文摘

We demonstrate that natural orbitals allow for reducing the computational cost of wave function based correlated calculations, especially for atoms and molecules in a large box, when a plane wave basis set under periodic boundary conditions is used. The employed natural orbitals are evaluated on the level of second-order M酶ller鈥揚lesset perturbation theory (MP2), which requires a computational effort that scales as (N⁵), where N is a measure of the system size. Moreover, we find that a simple approximation reducing the scaling to (N⁴) yields orbitals that allow for a similar reduction of the number of virtual orbitals. The MP2 natural orbitals are applied to coupled-cluster singles and doubles (CCSD) as well as full configuration interaction Quantum Monte Carlo calculations of the H₂ molecule to test our implementation. Finally, the atomization energies of the LiH molecule and solid are calculated on the level of MP2 and CCSD.