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Coupled cluster

About: Coupled cluster is a research topic. Over the lifetime, 6280 publications have been published within this topic receiving 301055 citations.


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Journal ArticleDOI
TL;DR: The convergence of ab initio predictions to the one-and n-particle limits has been systematically explored for several conformational energy prototypes as mentioned in this paper, including the inversion barriers of ammonia, water, and isocyanic acid, the torsional barrier of ethane, and the E/Z rotamer separation of formic acid.
Abstract: The convergence of ab initio predictions to the one- and n-particle limits has been systematically explored for several conformational energy prototypes: the inversion barriers of ammonia, water, and isocyanic acid, the torsional barrier of ethane, the E/Z rotamer separation of formic acid, and the barrier to linearity of silicon dicarbide. Explicit ab initio results were obtained with atomic-orbital basis sets as large as [7s6p5d4f3g2h1i/6s5p4d3f2g1h] and electron correlation treatments as extensive as fifth-order Mo/ller–Plesset perturbation theory (MP5), the full coupled-cluster method through triple excitations (CCSDT), and Brueckner doubles theory including perturbational corrections for both triple and quadruple excitations [BD(TQ)]. Subsequently, basis set and electron correlation extrapolation schemes were invoked to gauge any further variations in arriving at the ab initio limit. Physical effects which are tacitly neglected in most theoretical work have also been quantified by computations of non...

644 citations

Journal ArticleDOI
TL;DR: In this paper, state-of-the-art electronic structure theory has been applied to generate potential energy curves for the sandwich, T-shaped, and parallel-displaced configurations of the simplest prototype of aromas.
Abstract: State-of-the-art electronic structure theory has been applied to generate potential energy curves for the sandwich, T-shaped, and parallel-displaced configurations of the simplest prototype of arom...

638 citations

Journal ArticleDOI
TL;DR: The presence of substituents on the aromatic ring, irrespective of their electron withdrawing or donating nature, leads to an increase in the binding energy, and the displaced-stacked conformations are more stabilized than the T-shaped conformers, which explains the wide prevalence of displaced stacked structures in organic crystals.
Abstract: Interactions involving aromatic rings are important in molecular/biomolecular assembly and engineering. As a consequence, there have been a number of investigations on dimers involving benzene or other substituted π systems. In this Feature Article, we examine the relevance of the magnitudes of their attractive and repulsive interaction energy components in governing the geometries of several π−π systems. The geometries and the associated binding energies were evaluated at the complete basis set (CBS) limit of coupled cluster theory with singles, doubles, and perturbative triples excitations [CCSD(T)] using a least biased scheme for the given data set. The results for the benzene dimer indicate that the floppy T-shaped structure (center-to-center distance: 4.96 A, with an axial benzene off-centered above the facial benzene) is isoenergetic in zero-point-energy (ZPE) corrected binding energy (D0) to the displaced-stacked structure (vertical interplanar distance: 3.54 A). However, the T-shaped structure i...

602 citations

Journal ArticleDOI
TL;DR: In this article, a new implementation of local coupled-cluster theory with single and double excitations (LCCSD) is presented for which asymptotically all computational resources (CPU, memory, and disk) scale only linearly with the molecular size.
Abstract: A new implementation of local coupled-cluster theory with single and double excitations (LCCSD) is presented for which asymptotically all computational resources (CPU, memory, and disk) scale only linearly with the molecular size. This is achieved by: (i) restricting the correlation space for each electron pair to domains that are independent of molecular size; (ii) classifying the pairs according to a distance criterion and treating only strong pairs at the highest level; (iii) using efficient prescreening algorithms in the integral transformation and other integral-direct procedures; and (iv) neglect of small couplings of electron pairs that are far apart from each other. The errors caused by the various approximations are negligible. LCCSD calculations on molecules including up to 300 correlated electrons and over 1000 basis functions in C1 symmetry are reported, all carried out on a workstation.

592 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023163
2022351
2021267
2020344
2019253
2018244