دورية
The Lowest Singlet and Triplet States of o‐Benzyne: Spin‐Coupled Interpretation of the Electronic Structure at CAS SCF Equilibrium Geometries
| العنوان: | The Lowest Singlet and Triplet States of o‐Benzyne: Spin‐Coupled Interpretation of the Electronic Structure at CAS SCF Equilibrium Geometries |
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| المؤلفون: | Karadakov, Peter B., Gerratt, Joseph, Raos, Guido, Cooper, David L., Raimondi, Mario |
| المصدر: | Israel Journal of Chemistry; 1993, Vol. 33 Issue: 3 p253-264, 12p |
| مستخلص: | The electronic structure of the X̃1A1and ã3B2states of o‐benzyne is analyzed by means of spin‐coupled (SC) wave functions involving eight active orbitals: two at the dehydro centers, in the plane of the ring, and six π orbitals, inherited from benzene. The equilibrium geometries of the two states, at which all calculations have been carried out, result from separate full geometry optimizations employing ‘8 in 8’ complete active space self‐consistent field (CAS SCF) wave functions incorporating an analogous core‐valence partitioning. The diradical character of the ground state of o‐benzyne, as approximated by the singlet SC wave function, is reflected in the low value of the overlap (0.46) between the two in‐plane sp2‐like SC orbitals at the dehydro centers, which are just 1.274 Å apart, and in the nonnegligible extent of triplet coupling between the spins of the electrons in these orbitals — ca. 6.4% of the total spin function for the valence electrons (expressed in the Serber spin basis) is made up of spin eigenfunctions, in which these electrons enter as a triplet pair. The geometry of the ground state is found to have an aryne‐like character, which is further confirmed by the pattern of alternation of the overlaps between neighboring 71 valence orbitals, and by the domination of the total spin function for the valence electrons (expressed in the Rumer spin basis) by the spin‐coupling patterns corresponding to an arynic structure. |
| قاعدة البيانات: | Supplemental Index |
| تدمد: | 00212148 18695868 |
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| DOI: | 10.1002/ijch.199300032 |