TY  - JOUR
A1  - Pleß, V.
A1  - Suter, H. U.
A1  - Engels, Bernd
T1  - Ab initio study of the energy difference between the benzene and the cumulene form of the C\(_6\) molecule
N2  - The energy difference between the three lowest-lying isomers of C\(_6\) the linear \(^3 \sum ^-\) state and the two ring forms,the benzene structure (\(^1\)A\(_{18}\)) possessing D\(_{6h}\) symmetry and a distorted cyclic form ( \(^1\)A'\(_1\), D\(_{3h}\) symmetry) have been calculated using various ab initio methods. Variational methods such as multireference configuration interaction (MR-CI) and complete active space second order perturbatiOn treatment (CASPT2) have been applied, as weil as perturbational treatments and coupled cluster calculations (CCD). The correlation of all valence shell electrons is found to be important for a balanced description of the isomers of C\(_6\) . Methods which do not account for higher-order effects appropriately proved to be unsuitable for calculating the energy difference correctly. The results from multireference configuration interaction methods show that the isomers are close in energy with the cyclic forms somewhat lower than the linear form. The ring form possessing D\(_{3h}\) symmetry (\(^1\)A'\(_1\)} is found tobe the lowest-lying structure.
KW  - Organische Chemie
Y1  - 1994
UR  - https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/docId/5211
UR  - https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-59059
ER  -