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Electronic Absorption Spectra of Planar, Conjugated Biradicals in the Lowest Triplet State
Author(s) -
Gisin Markus,
Wirz Jakob
Publication year - 1983
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.19830660523
Subject(s) - chemistry , open shell , conjugated system , absorption spectroscopy , planar , triplet state , spectral line , absorption (acoustics) , electronic structure , configuration interaction , atomic physics , computational chemistry , molecular physics , molecule , organic chemistry , quantum mechanics , physics , computer graphics (images) , computer science , polymer , acoustics
The semiempirical PPP‐SCF‐SCI method has been adapted to even‐electron, open‐shell π‐systems by performing the SCF calculation on the lowest triplet configuration and choosing a limited set of single electronic excitations from the latter for configuration interaction. The basic approximations and parameters of the standard PPP model were retained. The results were compared with experimental triplet‐triplet absorption spectra of aromatic hydrocarbons and with more elaborate calculations available for selected systems. The reliability of the model was found to be comparable to its well‐known performance in predicting the absorption spectra of closed‐shell π‐systems and of conjugated radicals. Triplet‐state absorption spectra for various planar, conjugated biradicals were calculated and, where possible, compared with experimental data.