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Titolo:
Methodologies for computational studies of quininoidal diiminediyls: Biradical vs dinitrene behavior
Autore:
Lahti, PM; Ichimura, AS; Sanborn, JA;
Indirizzi:
Univ Massachusetts, Dept Chem, Amherst, MA 01003 USA Univ Massachusetts Amherst MA USA 01003 Dept Chem, Amherst, MA 01003 USA Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA Michigan State Univ E Lansing MI USA 48824 Chem, E Lansing, MI 48824 USA
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY A
fascicolo: 1, volume: 105, anno: 2001,
pagine: 251 - 260
SICI:
1089-5639(20010111)105:1<251:MFCSOQ>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONFIGURATION-INTERACTION CALCULATIONS; QUINONOIDAL DINITRENES; MOLECULAR CALCULATIONS; LOW-TEMPERATURE; RIGID MATRICES; BASIS SETS; FIELD; 4,4'-DIAZIDOBIPHENYL; HYDROCARBONS; PHOTOLYSIS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Lahti, PM Univ Massachusetts, Dept Chem, Amherst, MA 01003 USA Univ Massachusetts Amherst MA USA 01003 , Amherst, MA 01003 USA
Citazione:
P.M. Lahti et al., "Methodologies for computational studies of quininoidal diiminediyls: Biradical vs dinitrene behavior", J PHYS CH A, 105(1), 2001, pp. 251-260

Abstract

Density functional and post Hartree-Fock ab initio computations were carried out on the lowest singlet, triplet, and quintet states of 1,4-phenylenedinitrene, biphenyl-4,4'-dinitrene, (E)-stilbene-4,4'-dinitrene, and (E,E)-1,3-bis(4-nitrenophenyl)-1,3-butadiene, and (E,E,E)-1,6-bis(4-nitrenophenyl)-1,3,5-hexatriene. Near-degenerate singlet and triplet quinonoidal ground states were found for all systems using CASSCF methodology, with a slight favoring of the singlet, in accord with experimental results. The aromatic quintet dinitrene states lie much higher in energy. Restricted B3LYP hybrid density functional theory (DFT) methods give artifactually high biradical singlet state energies relative to the triplet biradical states, but unrestricted (mixed-state) B3LYP methods correctly give singlet energies that lie somewhat below the triplet state energies, as well as giving geometric results that compare well to the best CASSCF results we could achieve for these biradical states. Appropriate guidelines for selecting CASSCF versus DFT procedures in such cases are suggested in light of comparisons of computed toexperimental results.

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Documento generato il 26/09/20 alle ore 12:01:13