Journal ArticleDOI
The second stable conformer of 1,3-butadiene. Geometry optimizations with configuration interaction and coupled cluster methods
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TLDR
In this paper, the structures of s -cis and gauche butadiene have been determined using methods that include the effects of dynamical electron correlation, and the information yielded by the highest theoretical level used leads to a prediction that the gauche conformer is a minimum on the potential energy surface, lying 0.8 kcal/mol below the s-cis conformer which is predicted to be a transition state.About:
This article is published in Chemical Physics Letters.The article was published on 1989-09-22. It has received 33 citations till now. The article focuses on the topics: Pentane interference & Potential energy surface.read more
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Single-Bond Torsional Potentials in Conjugated Systems: A Comparison of ab Initio and Density Functional Results
TL;DR: The fully relaxed single-bond torsional potentials in typical conjugated systems were evaluated with the aid of ab initio self-consistent field and Moller−Plesset second-order calculations and, additionally, with several recently developed variants of the density functional theory as discussed by the authors.
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A study of some organic reactions using density functional theory
Jon Baker,Max Muir,Jan Andzelm +2 more
TL;DR: In this article, the authors used semi-empirical, traditional ab initio and density functional methodologies to study 12 organic reactions (six closed shell and six radical) and found that they provide a significant improvement over standard methods.
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Molecular mechanics (MM3) calculations on conjugated hydrocarbons
TL;DR: In this paper, the MM3 molecular mechanics program has been extended to conjugated systems and a VESCF method is applied to the pi-system to calculate bond orders, from which various stretching and torsional parameters are obtained.
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Molecular mechanics (MM4) calculations on conjugated hydrocarbons
TL;DR: The MM4 force field has been extended to conjugated hydrocarbon systems as mentioned in this paper, and it retains most of the formalism and computational schemes that were present in MM3.
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Ab initio studies of polyenes. I. 1,3‐butadiene
Hong Guo,Martin Karplus +1 more
TL;DR: In this article, the potential energy function about the C-C single bond of 1,3-butadiene was derived from ab initio calculations at both the Hartree-Fock (HF) level and the second-order Mo/ller-Plesset perturbation (MP2) level with 6.31G* basis set with complete geometry optimizations at each of 15 fixed CCCC dihedral angles.
References
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Gaussian Basis Functions for Use in Molecular Calculations. III. Contraction of (10s6p) Atomic Basis Sets for the First‐Row Atoms
TL;DR: In this paper, the effects of contraction on the energies and one-electron properties of the water and nitrogen molecules were investigated, and the authors obtained principles which can be used to predict optimal contraction schemes for other systems without the necessity of such exhaustive calculations.
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Gaussian‐Type Functions for Polyatomic Systems. II
Sigeru Huzinaga,Catalina Arnau +1 more
TL;DR: In this article, the use of a linear combination of Gaussian type orbitals (CGTO) instead of an individual Gaussian-type orbital (GTO) as a unit of basis functions for large-scale molecular calculations is discussed.
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Analytic evaluation of energy gradients for the single and double excitation coupled cluster (CCSD) wave function: Theory and application
TL;DR: The theory for the analytic evaluation of energy gradients for coupled cluster (CC) wave functions is presented in this paper, where explicit expressions for analytic energy gradient of the CC singles and doubles (CCSD) wave function for a closed-shell restricted Hartree-Fock reference determinant are presented and shown to scale as N6 where N is the one-electron number of atomic basis functions for the molecular system.
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Average structures of butadiene, acrolein, and glyoxal determined by gas electron diffraction and spectroscopy
TL;DR: In this paper, the electron diffraction intensities obtained in the present study and the rotational constants for several isotopic species reported in the literature have been analyzed by a least-squares method which combines them as joint observables.
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The closed‐shell coupled cluster single and double excitation (CCSD) model for the description of electron correlation. A comparison with configuration interaction (CISD) results
TL;DR: A single and double excitation coupled cluster (CCSD) method restricted to closed-shell single configuration reference functions is described in explicit detail in this article, where significant simplifications resulting from the restriction to closedshell systems are exploited to achieve maximum computational efficiency.