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The accuracy of rotational constants predicted by high-level quantum-chemical calculations. I. molecules containing first-row atoms
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A statistical analysis of the accuracy of theoretically predicted rotational constants is presented based on the data for a total of 16 molecules and 97 isotopologues, finding the importance of higher excitations, core correlation, and zero-point vibrational effects is emphasized, while the electronic contribution is found to be less important.Abstract:
A statistical analysis of the accuracy of theoretically predicted rotational constants is presented based on the data for a total of 16 molecules and 97 isotopologues. Special focus is given on the treatment of electron correlation by using coupled-cluster methods up to quadruple excitations, core correlation, basis-set effects, zero-point vibrational corrections, and the electronic contribution to the rotational constants. The high accuracy achieved in the present investigation is demonstrated by the fact that at our best theoretical level, termed as CCSD(T)cc-pV infinity Z+Delta core+DeltaT+DeltaQ+DeltaB vib+DeltaB el, the mean absolute error is 0.04% and the standard deviation is 0.07% in comparison with the available experimental data. The importance of higher excitations, core correlation, and zero-point vibrational effects is emphasized, while the electronic contribution is found to be less important.read more
Citations
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A Robust and Accurate Tight-Binding Quantum Chemical Method for Structures, Vibrational Frequencies, and Noncovalent Interactions of Large Molecular Systems Parametrized for All spd-Block Elements (Z = 1–86)
TL;DR: The accuracy of the method, called Geometry, Frequency, Noncovalent, eXtended TB (GFN-xTB), is extensively benchmarked for various systems in comparison with existing semiempirical approaches, and the method is applied to a few representative structural problems in chemistry.
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Recent advances in wave function-based methods of molecular-property calculations.
TL;DR: Recent Advances in Wave Function-Based Methods of Molecular-Property Calculations Trygve Helgaker, Poul Jørgensen, Kasper Kristensen, Jeppe Olsen, and Kenneth Ruud.
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Consistent structures and interactions by density functional theory with small atomic orbital basis sets
TL;DR: The new composite scheme (termed PBEh-3c) represents the next member in a hierarchy of "low-cost" electronic structure approaches, mainly free of BSSE and account for most interactions in a physically sound and asymptotically correct manner, and is suggested as a robust "high-speed" computational tool in theoretical chemistry and physics.
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Chemical accuracy in ab initio thermochemistry and spectroscopy: current strategies and future challenges
TL;DR: The current state of the art in wave function-based electronic structure methods is illustrated via discussions of the most important effects incorporated into a selection of high-accuracy methods chosen from the chemical literature as discussed by the authors.
Journal ArticleDOI
A survey of factors contributing to accurate theoretical predictions of atomization energies and molecular structures.
TL;DR: A survey of the widely varying magnitude of the most important components contributing to the atomization energies and structures of 106 small molecules is presented, which combines large Gaussian basis sets and coupled cluster theory up to quadruple excitations for all systems.
References
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Journal ArticleDOI
Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen
TL;DR: In this paper, a detailed study of correlation effects in the oxygen atom was conducted, and it was shown that primitive basis sets of primitive Gaussian functions effectively and efficiently describe correlation effects.
Journal ArticleDOI
A fifth-order perturbation comparison of electron correlation theories
TL;DR: In this paper, a new augmented version of coupled-cluster theory, denoted as CCSD(T), is proposed to remedy some of the deficiencies of previous augmented coupledcluster models.
Journal ArticleDOI
On the Correlation Problem in Atomic and Molecular Systems. Calculation of Wavefunction Components in Ursell-Type Expansion Using Quantum-Field Theoretical Methods
TL;DR: In this article, a method for the calculation of the matrix elements of the logarithm of an operator which gives the exact wavefunction when operating on the wavefunction in the one-electron approximation is proposed.
Journal ArticleDOI
Coupled-cluster theory in quantum chemistry
Rodney J. Bartlett,Monika Musiał +1 more
TL;DR: In this article, the essential aspects of coupled-cluster theory are explained and illustrated with informative numerical results, showing that the theory offers the most accurate results among the practical ab initio electronic-structure theories applicable to moderate-sized molecules.
Journal ArticleDOI
Gaussian basis sets for use in correlated molecular calculations. V. Core-valence basis sets for boron through neon
David E. Woon,Thom H. Dunning +1 more
TL;DR: In this article, the correlationconsistent polarized core-valence basis sets (cc•pVXZ) for the atoms boron through neon have been extended to treat core and core•valence correlation effects, and the exponents of the core functions were determined by minimizing the difference between allelectron and valence only correlation energies obtained from HF+1+2 calculations on the ground states of the atoms.
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