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Showing 1 to 11 of 11 for “"Many-body methods"”.
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Advancements in Monte Carlo many body methods
Many-body methods are one of the most powerful tools that may be brought to bear to solve the electronic structure problem. While both of the following theories provide a complete path to obtain any quantity, many-body perturbation theory is principally used to provide molecular energies, while …
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Advancing many-body methods for electronic structure calculations
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-02-04 without embargo terms
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Diagrammatic many-body methods for anharmonic molecular vibrational properties
Diagrammatic many-body methods for computing the energies and other properties of anharmonic vibrations have been developed based on the Dyson equation formalism for the single-particle vibrational Green's function and the many-body perturbation theory for the total zero-point energy. Unlike …
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Vibrational many-body methods for molecules and extended systems
"Vibrational many-body methods for molecules and extended systems have been developed that can account for the effects of anharmonicity in the potential energy surfaces (PESs) on energies and other observable properties. For molecules, we present a general scheme to calculate anharmonic vibrational …
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Efficient automated implementation of higher-order many-body methods in quantum chemistry
… models with approx- imate inclusion of 3-body clusters [J. Chem. Phys. 151, 064102 (2019)] we performed a more complete assessment of the 3CC method [J. Chem. Phys. 125, 204105 (2006)] for accurate computational thermochemistry in the standard HEAT framework. New spin- integrated …
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First-principles and Many-Body Methods: Implementations and Applications to Study Spintronic Materials
… material Ta2PdSe6 with first-principle and many-body methods. Particularly, we investigate the Mn valence in (Ga,Mn)N and derive low-energy models of (Ga,Mn)N by making use of a first-principles Wannier-function analysis. Additionally, we also study the disorder-driven localization in DMSs …
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Finite-temperature many-body perturbation theory for electrons
… second-order corrections from finite-temperature many-body perturbation theory described in textbooks were found to be not identical to the benchmark λ-variation results calling into question the validity of this theory. The results obtained from renormalized finite-temperature perturbation theory …
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Exploration and Optimization of the One- and Many-particle Basis Sets in Modern Explicitly Correlated Electronic Structure
… electronic structure calculations. Despite the many development producing methods that circumvent the issue by using grids or real-space methods, the linear combination of atomic orbitals (LCAO) approach using Gaussian atomic basis sets is still the most popular method for the simplicity of the …
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Diagrammatic theories for the vibrational many-body problem
Anharmonic vibrational many-body methods are developed for and applied to small molecules and extended systems in a bound potential energy surface (PES). Diagrammatically size-consistent and basis-set-free vibrational coupled-cluster (XVCC) theory for both zero-point energies and transition …
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Modern Electronic Structure Theory using Tensor Product States
… simulation on large systems. However, in many cases, the Hilbert space can be partitioned into clusters on the basis of strong and weak interactions. In this work, we mainly focus on an approach where we partition the system into smaller orbital clusters in which we can define …
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In Pursuit of Local Correlation for Reduced-Scaling Electronic Structure Methods in Molecules and Periodic Solids
… system size. In the case of Hartree-Fock, a one-body wavefunction-based method, the scaling is formally N⁴, and post-Hartree-Fock methods fare even worse. The coupled cluster singles, doubles, and perturbative triples method [CCSD(T)], which is frequently referred to as the "gold standard" of …