TITLE

Electron–intramolecular-phonon coupling and possible superconductivity in negatively charged coronene and corannulene

AUTHOR(S)
Kato, Takashi; Yamabe, Tokio
PUB. DATE
August 2002
SOURCE
Journal of Chemical Physics;8/1/2002, Vol. 117 Issue 5, p2324
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Electron-intramolecular-phonon coupling and its role in the occurrence of possible superconductivity in the monoanions of coronene (C[sub 24]H[sub 12]) and corannulene (C[sub 20]H[sub 10]) are studied. Electron-intramolecular-phonon coupling constants are calculated from the intramolecular vibronic coupling constants. The C-C stretching E[sub 2g] mode of 1668 cm[sup -1] plays an essential role in the electron-intramolecular-phonon coupling in the monoanion of coronene while the low frequency E[sub 2] modes, which have a radial character, and the C-C stretching mode of 1669 cm[sup -1], which has a tangential character, afford large electron-intramolecular-phonon coupling constants in the monoanion of corannulene. The calculated total electron-intramolecular-phonon coupling constant for the monoanion of corannulene (0.269 eV) is much larger than that for coronene monoanion (0.076 eV). The intermediate characteristics between σ and π orbital interaction properties owing to the bowl-shaped structure of corannulene make orbital interactions between two neighboring carbon atoms strong, and thus electron-intramolecular-phonon coupling is stronger in the monoanion of corannulene than that in the monoanion of coronene. Possible superconducting transition temperature T[sub c] value for the monoanion of corannulene is estimated to be an order of magnitude larger than that for the monoanion of coronene; for example, the calculated values of T[sub c]s for the monoanions of coronene and corannulene are about 0.05-8.86 and 29.17-65.56 K, respectively, in the range of n(0)=4-5 and μ[sup *]= 0.10-0.20, where n(0) is the density of states at the Fermi level (states per eV, per spin, and per molecule) and μ[sup *] is the Coulomb pseudopotential. The relationships between structures and T[sub c]s in alkali-doped A[sub 3] C[sub 60] complexes and graphite intercalation compounds (GICs) are also discussed from a viewpoint that corannulene can be viewed as a fragment of...
ACCESSION #
6985584

 

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