Cyclobutadiene automerization and rotation of ethylene: Energetics of the barriers by using Spin-polarized wave functions
Article first published online: 10 MAY 2014
Copyright © 2014 Wiley Periodicals, Inc.
Journal of Computational Chemistry
Volume 35, Issue 18, pages 1356–1363, 5 July 2014
How to Cite
How to cite this article: J. Comput. Chem. 2014, 35, 1356–1363. DOI: 10.1002/jcc.23630, .
- Issue published online: 5 JUN 2014
- Article first published online: 10 MAY 2014
- Manuscript Accepted: 14 APR 2014
- Manuscript Revised: 10 APR 2014
- Manuscript Received: 5 MAR 2014
- Spanish MCYT. Grant Numbers: FIS2009-10325, FIS2012-35880
- spin-polarized wave functions;
- spin-projected calculations;
- electron correlation
Spin-projected spin polarized Møller–Plesset and spin polarized coupled clusters calculations have been made to estimate the cyclobutadiene automerization, the ethylene torsion barriers in their ground state, and the gap between the singlet and triplet states of ethylene. The results have been obtained optimizing the geometries at MP4 and/or CCSD levels, by an extensive Gaussian basis set. A comparative analysis with more complex calculations, up to MP5 and CCSDTQP, together with others from the literature, have also been made, showing the efficacy of using spin-polarized wave functions as a reference wave function for Møller–Plesset and coupled clusters calculations, in such problems. © 2014 Wiley Periodicals, Inc.