The influence of orbital rotation on the energy of closed-shell wavefunctions
- Author
- Peter A Limacher, Taewon D Kim, Paul W Ayers, Paul Johnson (UGent) , Stijn De Baerdemacker (UGent) , Dimitri Van Neck (UGent) and Patrick Bultinck (UGent)
- Organization
- Abstract
- The orbital dependence of closed-shell wavefunction energies is investigated by performing doubly-occupied configuration interaction (DOCI) calculations, representing the most general class of these wavefunctions. Different local minima are examined for planar hydrogen clusters containing two, four, and six electrons applying (spin) symmetry-broken restricted, unrestricted, and generalised orbitals with real and complex coefficients. Contrary to Hartree-Fock (HF), restricted DOCI is found to properly break bonds and thus unrestricted orbitals, while providing a quantitative improvement of the energy, are not needed to enforce a qualitatively correct bond dissociation. For the beryllium atom and the BH diatomic, the lowest possible HF energy requests symmetry-broken generalised orbitals, whereas accurate results for DOCI can be obtained within a restricted formalism. Complex orbital coefficients are shown to increase the accuracy of HF and DOCI results in certain cases. The computationally inexpensive AP1roG geminal wavefunction is proven to agree very well with all DOCI results of this study.
- Keywords
- MODEL, static electron correlation, closed-shell wavefunction, doubly-occupied configuration interaction, orbital optimisation, MOLECULES, MATRIX, NONORTHOGONAL GEMINALS, SYSTEMS, MCSCF METHODS, BERYLLIUM ATOM, EQUATIONS, EXCITED-STATES
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Citation
Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-4397928
- MLA
- Limacher, Peter A., et al. “The Influence of Orbital Rotation on the Energy of Closed-Shell Wavefunctions.” MOLECULAR PHYSICS, vol. 112, no. 5–6, 2014, pp. 853–62, doi:10.1080/00268976.2013.874600.
- APA
- Limacher, P. A., Kim, T. D., Ayers, P. W., Johnson, P., De Baerdemacker, S., Van Neck, D., & Bultinck, P. (2014). The influence of orbital rotation on the energy of closed-shell wavefunctions. MOLECULAR PHYSICS, 112(5–6), 853–862. https://doi.org/10.1080/00268976.2013.874600
- Chicago author-date
- Limacher, Peter A, Taewon D Kim, Paul W Ayers, Paul Johnson, Stijn De Baerdemacker, Dimitri Van Neck, and Patrick Bultinck. 2014. “The Influence of Orbital Rotation on the Energy of Closed-Shell Wavefunctions.” MOLECULAR PHYSICS 112 (5–6): 853–62. https://doi.org/10.1080/00268976.2013.874600.
- Chicago author-date (all authors)
- Limacher, Peter A, Taewon D Kim, Paul W Ayers, Paul Johnson, Stijn De Baerdemacker, Dimitri Van Neck, and Patrick Bultinck. 2014. “The Influence of Orbital Rotation on the Energy of Closed-Shell Wavefunctions.” MOLECULAR PHYSICS 112 (5–6): 853–862. doi:10.1080/00268976.2013.874600.
- Vancouver
- 1.Limacher PA, Kim TD, Ayers PW, Johnson P, De Baerdemacker S, Van Neck D, et al. The influence of orbital rotation on the energy of closed-shell wavefunctions. MOLECULAR PHYSICS. 2014;112(5–6):853–62.
- IEEE
- [1]P. A. Limacher et al., “The influence of orbital rotation on the energy of closed-shell wavefunctions,” MOLECULAR PHYSICS, vol. 112, no. 5–6, pp. 853–862, 2014.
@article{4397928, abstract = {{The orbital dependence of closed-shell wavefunction energies is investigated by performing doubly-occupied configuration interaction (DOCI) calculations, representing the most general class of these wavefunctions. Different local minima are examined for planar hydrogen clusters containing two, four, and six electrons applying (spin) symmetry-broken restricted, unrestricted, and generalised orbitals with real and complex coefficients. Contrary to Hartree-Fock (HF), restricted DOCI is found to properly break bonds and thus unrestricted orbitals, while providing a quantitative improvement of the energy, are not needed to enforce a qualitatively correct bond dissociation. For the beryllium atom and the BH diatomic, the lowest possible HF energy requests symmetry-broken generalised orbitals, whereas accurate results for DOCI can be obtained within a restricted formalism. Complex orbital coefficients are shown to increase the accuracy of HF and DOCI results in certain cases. The computationally inexpensive AP1roG geminal wavefunction is proven to agree very well with all DOCI results of this study.}}, author = {{Limacher, Peter A and Kim, Taewon D and Ayers, Paul W and Johnson, Paul and De Baerdemacker, Stijn and Van Neck, Dimitri and Bultinck, Patrick}}, issn = {{0026-8976}}, journal = {{MOLECULAR PHYSICS}}, keywords = {{MODEL,static electron correlation,closed-shell wavefunction,doubly-occupied configuration interaction,orbital optimisation,MOLECULES,MATRIX,NONORTHOGONAL GEMINALS,SYSTEMS,MCSCF METHODS,BERYLLIUM ATOM,EQUATIONS,EXCITED-STATES}}, language = {{eng}}, number = {{5-6}}, pages = {{853--862}}, title = {{The influence of orbital rotation on the energy of closed-shell wavefunctions}}, url = {{http://doi.org/10.1080/00268976.2013.874600}}, volume = {{112}}, year = {{2014}}, }
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