Journal ArticleDOI
Avoiding the integral storage bottleneck in LCAO calculations of electron correlation
Svein Saebo,Jan Almlöf +1 more
TLDR
In this article, a method for obtaining electron-repulsion integrals over a molecular-orbital basis without any explicit four-index transformation involving input/output is proposed, which allows for calculations that would otherwise be prohibited by storage limitations with conventional techniques.About:
This article is published in Chemical Physics Letters.The article was published on 1989-01-06. It has received 697 citations till now. The article focuses on the topics: Basis function.read more
Citations
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Journal ArticleDOI
Electronic structure calculations on workstation computers: the program system turbomole
TL;DR: TURBOMOLE as discussed by the authors is a program system for SCF that takes full advantage of all discrete point group symmetries and has only modest I/O and background storage requirements.
Journal ArticleDOI
A direct MP2 gradient method
TL;DR: In this article, a direct method for evaluating the gradient of the second-order Moller-Plesset (MP2) energy without storing any quartic quantities, such as two-electron repulsion integrals (ERIs), double substitution amplitudes or the two-particle density matrix, was presented.
Journal ArticleDOI
A comparison of the efficiency and accuracy of the quadratic configuration interaction (QCISD), coupled cluster (CCSD), and Brueckner coupled cluster (BCCD) methods
TL;DR: In this article, the Brueckner coupled-cluster (BCCD) method with single and double excitations from a closed-shell reference function (CCSD) and the corresponding quadratic configuration interaction method (QCISD) are formulated in terms of quantities which can be computed directly from the two-electron integrals in AO basis.
Journal ArticleDOI
Semi-direct algorithms for the MP2 energy and gradient
TL;DR: In this paper, the authors formulate semi-direct MP2 methods that utilize disk space (which is usually much larger than memory size) for the steps that require most storage, and show that these methods are superior to conventional algorithms despite requiring less disk space.
Journal ArticleDOI
The molecular basis of working mechanism of natural polyphenolic antioxidants
TL;DR: In this article, a summary of the research work performed so far using high accuracy quantum chemical methods on polyphenolic antioxidant compounds is presented, which represents a further important contribution to elucidation of the beneficial effects on health of these substances.
References
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Journal ArticleDOI
Self‐consistent molecular orbital methods. XX. A basis set for correlated wave functions
TL;DR: In this article, a contract Gaussian basis set (6•311G) was developed by optimizing exponents and coefficients at the Mo/ller-Plesset (MP) second-order level for the ground states of first-row atoms.
Journal ArticleDOI
General contraction of Gaussian basis sets. I. Atomic natural orbitals for first- and second-row atoms
Jan Almlöf,Peter R. Taylor +1 more
TL;DR: In this paper, a general contraction scheme for Gaussian basis sets is presented, where the contraction coefficients are defined by the natural orbitals obtained from an atomic configuration interaction calculation, which provides an excellent basis for molecular electronic structure calculations, and large primitive sets can be contracted to only a few functions without significant loss in either the SCF or correlation energy.
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Principles for a direct SCF approach to LICAO–MOab-initio calculations
TL;DR: In this article, the principles and structure of an LCAO-MO ab-initio computer program which recalculates all two-electron integrals needed in each SCF iteration are formulated and discussed.
Journal ArticleDOI
Orbital-invariant formulation and second-order gradient evaluation in MOller-Plesset perturbation theory
Peter Pulay,Svein Saebo +1 more
TL;DR: In this article, the second and third orders of Moller-Plesset perturbation theory are reformulated in terms of arbitrary (e.g., localized) internal orbitals, and atomic orbitals in the virtual space.
Journal ArticleDOI
Fourth‐order Mo/ller–Plessett perturbation theory in the local correlation treatment. I. Method
Svein Saebo,Peter Pulay +1 more
TL;DR: In this article, the authors formulated the MP4 theory for localized internal orbitals of closed-shell systems and showed that it is strictly identical with canonical MP4 if no further approximations are made.