Note on an Approximation Treatment for Many-Electron Systems
Chr. Møller,Milton S. Plesset +1 more
TLDR
In this article, a perturbation theory for treating a system of n electrons in which the Hartree-Fock solution appears as the zero-order approximation was developed, and it was shown by this development that the first order correction for the energy and the charge density of the system is zero.Abstract:
A perturbation theory is developed for treating a system of n electrons in which the Hartree-Fock solution appears as the zero-order approximation. It is shown by this development that the first order correction for the energy and the charge density of the system is zero. The expression for the second-order correction for the energy greatly simplifies because of the special property of the zero-order solution. It is pointed out that the development of the higher approximation involves only calculations based on a definite one-body problem.read more
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Double‐hybrid density functionals
Lars Goerigk,Stefan Grimme +1 more
TL;DR: Double-hybrid density functionals (DHDFs) are reviewed in this paper, where the contribution of nonlocal Fock-exchange and second-order perturbative correlation is replaced by contributions from nonlocal perturbation correlation.
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Infrared Spectroscopic Study of Vibrational Modes in Methylammonium Lead Halide Perovskites
Tobias Glaser,Christian Müller,Michael Sendner,Christian Krekeler,Octavi E. Semonin,Trevor D. Hull,Omer Yaffe,Jonathan S. Owen,Wolfgang Kowalsky,Annemarie Pucci,Robert Lovrincic +10 more
TL;DR: High-quality infrared spectroscopic measurements of methylammonium lead halide perovskite films and single crystals at room temperature are reported, from which the dielectric function in the investigated spectral range is derived.
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The choice of a zeroth-order Hamiltonian for second-order perturbation theory with a complete active space self-consistent-field reference function
TL;DR: In this article, the use of a zeroth-order Hamiltonian for second-order perturbation with a complete active space self-consistent field (CASSCF) reference function is discussed in detail.
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Theory and application of explicitly correlated Gaussians
Jim Mitroy,Sergiy Bubin,Wataru Horiuchi,Yasuyuki Suzuki,Ludwik Adamowicz,Wojciech Cencek,Krzysztof Szalewicz,Jacek Komasa,D Blume,Kalman Varga +9 more
TL;DR: The variational method complemented with the use of explicitly correlated Gaussian basis functions is one of the most powerful approaches currently used for calculating the properties of few-body systems as mentioned in this paper.
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Anchoring the water dimer potential energy surface with explicitly correlated computations and focal point analyses
Gregory S. Tschumper,Matthew L. Leininger,Brian C. Hoffman,Edward F. Valeev,Henry F. Schaefer,Martin Quack +5 more
TL;DR: In this paper, the authors characterized ten stationary points on the water dimer potential energy surface with the coupled-cluster technique, including all single and double excitations as well as a perturbative approximation of triple excitations.