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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: In this article, molecular quantum mechanics has been applied to the unimolecular dissociation of H2CO and triple zeta plus double polarization (TZ+2P) basis set was used in conjunction with complete optimization of all stationary point geometries.
Abstract: Ab initio molecular quantum mechanics has been applied to the unimolecular dissociation of H2CO. Basis sets as large as triple zeta plus double polarization (TZ+2P) were used in conjunction with complete optimization of all stationary point geometries. The classical barrier height is predicted with the TZ+2P basis set to be 101.9 (SCF), 95.0 (CISD), 90.4 (CCSD), and 86.8 kcal/mol (CCSDT‐1). With correction for zero‐point vibrational energies, the activation energy is predicted to be 81.4 kcal/mol, in good agreement with experimental estimates.

107 citations

Journal ArticleDOI
TL;DR: The electronic structure and properties of the silabenzenes series have been investigated using basis sets of spdf quality and many-body perturbation theory, hybrid density functional theory, and coupled cluster methods.

107 citations

Journal ArticleDOI
TL;DR: In this article, a quantitative survey on the performance of multireference (MR), configuration interaction with all singles and doubles (CISD), MRCISD with the Davidson correction and MR-average quadratic coupled cluster (AQCC) methods for a wide range of excited states of the diatomic molecules B2, C2, N2 and O2 is presented.
Abstract: A quantitative survey on the performance of multireference (MR), configuration interaction with all singles and doubles (CISD), MRCISD with the Davidson correction and MR-average quadratic coupled cluster (AQCC) methods for a wide range of excited states of the diatomic molecules B2, C2, N2 and O2 is presented. The spectroscopic constants r e, ωe, T e and D e for a total of 60 states have been evaluated and critically compared with available experimental data. Basis set extrapolations and size-extensivity corrections are essential for highly accurate results: MR-AQCC mean-errors of 0.001 A, 10 cm−1, 300 cm−1 and 300 cm−1 have been obtained for r e, ωe, T e and D e, respectively. Owing to the very systematic behavior of the results depending on the basis set and the choice of method, shortcomings of the calculations, such as Rydberg state coupling or insufficient configuration spaces, can be identified independently of experimental data. On the other hand, significant discrepancies with experiment for states which indicate no shortcomings whatsoever in the theoretical treatment suggest the re-evaluation of experimental results. The broad variety of states included in our survey and the uniform quality of the results indicate that the observed systematics is a general feature of the methods and, hence, is molecule-independent.

107 citations

Journal ArticleDOI
TL;DR: The method referred to as the non-Dyson third-order algebraic-diagrammatic construction [nD-ADC(3)] approximation for the electron propagator represents a computationally promising alternative to the existing Dyson ADC(3) method.
Abstract: An earlier proposed propagator method for the treatment of molecular ionization is tested in first applications. The method referred to as the non-Dyson third-order algebraic-diagrammatic construction [nD-ADC(3)] approximation for the electron propagator represents a computationally promising alternative to the existing Dyson ADC(3) method. The advantage of the nD-ADC(3) scheme is that the (N+/-1)-electronic parts of the one-particle Green's function are decoupled from each other and the corresponding equations can be solved separately. For a test of the method the nD-ADC(3) results for the vertical ionization transitions in C(2)H(4), CO, CS, F(2), H(2)CO, H(2)O, HF, N(2), and Ne are compared with available experimental and theoretical data including results of full configuration interaction (FCI) and coupled cluster computations. The mean error of the nD-ADC(3) ionization energies relative to the experimental and FCI results is about 0.2 eV. The nD-ADC(3) method, scaling as n(5) with the number of orbitals, requires the solution of a relatively simple Hermitian eigenvalue problem. The method renders access to ground-state properties such as dipole moments. Moreover, also one-electron properties of (N+/-1) electron states can now be studied as a consequence of a specific intermediate-state representation (ISR) formulation of the nD-ADC approach. Corresponding second-order ISR equations are presented.

107 citations

Journal ArticleDOI
TL;DR: The performance and some of the potentialities of the approach are investigated in calculations of the visible/ultraviolet absorption spectrum and the dispersion of the real polarizability in near-resonant regions of pyrimidine, the near-edge absorption fine structure (NEXAFS) of ammonia, and the direct determination of the C6 dipole-dipole dispersion coefficient of the benzene dimer.
Abstract: We present an implementation of the damped coupled-cluster linear response function based on an asymmetric Lanczos chain algorithm for the hierarchy of coupled-cluster approximations CCS (coupled-c ...

107 citations


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