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Accurate ab initio calculations for the 1B1-1A1 separation in methylene
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In this paper, a 1B1-1B1 separation of methylene was determined using ab initio calculations with a basis set of better than triple-zeta quality and two sets of polarization functions.About:
This article is published in Chemical Physics Letters.The article was published on 1980-09-01. It has received 22 citations till now. The article focuses on the topics: Ab initio quantum chemistry methods.read more
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Density functional theory: coverage of dynamic and non-dynamic electron correlation effects
TL;DR: In this paper, it was shown that the long range correlation effects are caused by the self-interaction error (SIE) of standard X functionals, and that the exchange SIE is responsible for the fact that DFT densities often resemble MP4 or MP2 densities.
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Can Unrestricted Density-Functional Theory Describe Open Shell Singlet Biradicals?
TL;DR: In this paper, the authors used restricted density functional theory (UDFT) for the description of open-shell singlet (OSS) biradicals provided a number of precautions are considered.
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Geometry and singlet−triplet energy gap in methylene: a critical review of experimental and theoretical determinations
TL;DR: In this article, the experimental and theoretical attempts to determine the equilibrium bond angle in the 3B1 ground state and the 1A1-3B1 energy gap between the lowest two states of the methylene molecule are reviewed.
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The combination of density functional theory with multi-configuration methods - CAS-DFT
Jürgen Gräfenstein,Dieter Cremer +1 more
TL;DR: CAS-DFT as mentioned in this paper is a method that allows an economical simultaneous treatment of static and dynamic correlation effects in molecules with multi-reference character, and it has been shown to work reasonably for the ring opening of dioxirane and the excitation energies of methylene.
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Can density functional theory describe multi-reference systems? Investigation of carbenes and organic biradicals
Jürgen Gräfenstein,Dieter Cremer +1 more
TL;DR: In this paper, the advantages and limitations of the restricted open-shell singlet (ROSS) formalism and the complete active space density functional theory (CAS-DFT) for multi-reference problems are discussed.
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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The iterative calculation of several of the lowest or highest eigenvalues and corresponding eigenvectors of very large symmetric matrices
TL;DR: The coordinate relaxation method for the iterative calculation of the lowest (or highest) root of a symmetric matrix, based on the minimization (or maximization) of the Rayleigh quotient, has been generalized to make it possible to obtain several of the highest roots in order without explicitly modifying the original matrix.
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Laser photoelectron spectrometry of methylene(1-). Singlet-triplet splitting and electron affinity of methylene
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Valence excited states of CH. I. Potential curves
TL;DR: In this article, the potential curves for the first five valence excited states of CH; X2Π, a4Σ−1, A2Δ, B2Σ+ and C2+ were obtained over a wide range of internuclear distances.