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Das Absorptionsspektrum des Radialens
Author(s) -
Weltin E.,
Gerson F.,
Murrell J. N.,
Heilbronner E.
Publication year - 1961
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19610440527
Subject(s) - chemistry , planar , cyclohexane , atomic orbital , molecular orbital , molecule , excited state , singlet state , symmetry (geometry) , absorption band , crystallography , atomic physics , physics , electron , optics , geometry , computer graphics (images) , mathematics , organic chemistry , quantum mechanics , computer science
H ÜCKEL and SCF molecular orbitals habe been evaluated for radialene, the parent hydrocarbon of hexamethyl‐radialene (hexaethylidene‐cyclohexane). The energies of the excited singlet states of this molecule have been calculated by the P ARISER ‐ PARR method and also by considering the molecule to be made up of six weakly coupled ethylene fragments. The results are compared with the observed spectrum of hexamethyl‐radialene. Both theoretical treatments show that the first absorption band at 38500 cm −l has symmetry B 1u (in D 6u or A 2u (in D 3d ) which corresponds to a forbidden transition for the planar structure, but is allowed in the puckered D 3d configuration. The more intense band at 48800 cm −l is probably E 1u (in D 6h ) or E u (in D 3d ) and is allowed in both the planar and the puckered configurations.