Multireference calculations for ring inversion and double bond shifting in cyclooctatetraene

• Published in: Journal of computational chemistry Vol. 34; no. 16; pp. 1393 - 1397
• Main Authors: Schild, Axel, Paulus, Beate
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 15.06.2013; Wiley Subscription Services, Inc
• Subjects: CASPT3; Chemical bonds; Chemistry; Computational mathematics; Correlation analysis; Cyclooctanes - chemistry; cyclooctatetraene; double bond shifting; dynamical correlations; Mathematical analysis; Quantum Theory; ring inversion
• ISSN: 0192-8651; 1096-987X
• DOI: 10.1002/jcc.23273

We present multireference calculations for the characterization of ring inversion and double bond shifting in cyclooctatetraene. The results show that it is necessary to treat the dynamical correlation very accurately to obtain correct values for the barrier heights. This can be done, for example, with multireference configuration interaction or with perturbation theory of third order. However, detailed analysis also shows that already a complete active space self‐consistent field treatment describes the processes surprisingly well. Thus, this method could be used as a computationally cheap method, for example, for dynamics simulations. © 2013 Wiley Periodicals, Inc. In its electronic ground state, ring inversion and double bond shifting occur in cyclooctatetraene, as shown schematically in the picture. Multireference calculation methods are used to determine the relevant structures of the ground state potential energy surface for these processes. The level at which dynamical and static electron correlations have to be treated to allow faithful numerical results is also investigated.