Journal ArticleDOI
Ab initio calculations of small hydrides including electron correlation: VI. Study of the correlation energy of the BH ground state and its dependence on the internuclear distance
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This article is published in Theoretical Chemistry Accounts.The article was published on 1971-01-01. It has received 26 citations till now. The article focuses on the topics: Ground state & Ab initio quantum chemistry methods.read more
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PNO–CI Studies of electron correlation effects. I. Configuration expansion by means of nonorthogonal orbitals, and application to the ground state and ionized states of methane
TL;DR: In this paper, the convergence of the configuration expansion of a many-electron wave function was improved without significantly complicating the energy matrix elements by using partially non-orthogonal orbitals.
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Exploring the Accuracy Limits of Local Pair Natural Orbital Coupled-Cluster Theory
TL;DR: This work investigates how far the accuracy of the DLPNO–CCSD(T) method can be pushed for chemical applications and addresses the question at which additional computational cost improvements, relative to the previously established default scheme, come.
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PNO–CI and CEPA studies of electron correlation effects. III. Spectroscopic constants and dipole moment functions for the ground states of the first‐row and second‐row diatomic hydrides
Wilfried Meyer,Pavel Rosmus +1 more
TL;DR: In this paper, a systematic investigation of the ground state potential curves and dipole moment functions has been performed for the diatomic hydrides LiH to HCl on the basis of variational configuration interaction wavefunctions PNO-CI and the coupled electron pair approximation CEPA.
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PNO–CI (pair natural orbital configuration interaction) and CEPA–PNO (coupled electron pair approximation with pair natural orbitals) calculations of molecular systems. I. Outline of the method for closed‐shell states
TL;DR: In this paper, the authors improved the methods of configuration interaction with double substitutions to pair natural orbitals (PNO−CI) and of the coupled electron pair approximation (CEPA) proposed by W. Meyer by combination with a new scheme of the calculation of the pair NPs (PNOs) and an efficient iterative scheme for the diagonalization of the CI matrix.
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PNO–CI (pair natural orbital configuration interaction) and CEPA–PNO (coupled electron pair approximation with pair natural orbitals) calculations of molecular systems. II. The molecules BeH2, BH, BH3, CH4, CH−3, NH3 (planar and pyramidal), H2O, OH+3, HF and the Ne atom
TL;DR: In this paper, the Hartree-Fock limits for the molecular energies are estimated for the unknown molecules MgH2 and AlH3, and binding energies, equilibrium geometries, and symmetric-stretching force constants are predicted.
References
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Electronic Structure of Diatomic Molecules. VII.A. Hartree—Fock Wavefunctions and Energy Quantities for the Ground States of the Second‐Row Hydrides, AH
Paul E. Cade,Winifred M. Huo +1 more
TL;DR: In this article, Hartree-Fock wavefunctions are presented for the NaH(X1Σ+), MgH (X2Σ+) and AlH(AlH+), SiH(H2Πr), PH(X3Σ−), SH(X 2Πi), and HCl(X 1 Σ+) molecules.
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Gaussian Lobe Function Expansions of Hartree—Fock Solutions for the First‐Row Atoms and Ethylene
TL;DR: In this paper, the first row atoms are determined by a self-consistent field minimization of atomic energies, which is achieved by defining origins for the basis functions at points in space determined by the symmetry of the orbital to be expanded.
Journal ArticleDOI
Studies in Configuration Interaction: The First-Row Diatomic Hydrides
TL;DR: In this paper, the first-row diatomic hydrides, calculated with accurate configuration-interaction wave functions, were determined at the equilibrium internuclear separation for each molecule and the basis sets used, were capable of reproducing recently published selfconsistent field energies to within 0003 hartrees.
Journal ArticleDOI
NATURE OF THE CONFIGURATION-INTERACTION METHOD IN AB INITIO CALCULATIONS. I. Ne GROUND STATE.
Tery L. Barr,Ernest R. Davidson +1 more
TL;DR: In this article, a detailed study of the correlation energy of Ne has been made in order to analyze the nature of the configurationinteraction (CI) method in ab initio calculations, and both the Bethe-Goldstone method of Nesbet and the total-pair-excitation-block method (TPEB) were examined.
Related Papers (5)
Ab initio calculations on small hydrides including electron correlation: III. A study of the valence shell intrapair and interpair correlation energy of some first row hydrides
M. Jungen,R. Ahlrichs +1 more