Electron-intramolecular-phonon coupling and possible superconductivity in negatively charged coronene and corannulene
Electron-intramolecular-phonon coupling and possible superconductivity in negatively charged coronene and corannulene
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DOI：
10.1063/1.1489899
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发表时间：
2002-08-01
影响因子：
4.4
通讯作者：
Yamabe, T
中科院分区：
文献类型：
--
作者：
Kato, T;Yamabe, T
研究了电子-分子内-声子耦合及其在晕苯 (C24H12) 和晕晕烯 (C20H10) 单阴离子中可能出现的超导性中的作用。电子-分子内-声子耦合常数是根据分子内振动耦合常数计算的。 1668 cm(-1)的C-C伸缩E-2g模式在晕苯单阴离子中的电子-分子内-声子耦合中起着至关重要的作用，而具有径向特征的低频E-2模式和具有切向特征的1669 cm(-1)的C-C伸缩模式在晕苯单阴离子中提供了大的电子-分子内声子耦合常数。计算得出的晕晕烯单阴离子总电子-分子内声子耦合常数 (0.269 eV) 远大于晕晕烯单阴离子 (0.076 eV)。由于冠烯的碗状结构，其介于 sigma 和 pi 轨道相互作用性质之间的中间特性使得两个相邻碳原子之间的轨道相互作用较强，因此冠烯单阴离子中的电子-分子内-声子耦合比晕烯单阴离子中的电子-分子内-声子耦合更强。据估计，晕烯单阴离子的可能超导转变温度 T-c 值比晕烯单阴离子的超导转变温度 T-c 值大一个数量级；例如，在n(0)=4-5和mu*=0.10-0.20范围内，晕苯和晕晕烯单阴离子的T(c)s计算值分别约为0.05-8.86和29.17-65.56 K，其中n(0)是费米能级的态密度（每eV、每自旋和每分子的态密度），mu*是费米能级的态密度。库仑赝势。碱掺杂的A(3)C(60)配合物和石墨插层化合物(GIC)中的结构和T(c)之间的关系也从corannulene可以被视为C-60的碎片和晕苯可以被视为单片石墨的碎片的角度进行了讨论。 (C) 2002 年美国物理研究所。
Electron-intramolecular-phonon coupling and its role in the occurrence of possible superconductivity in the monoanions of coronene (C24H12) and corannulene (C20H10) are studied. Electron-intramolecular-phonon coupling constants are calculated from the intramolecular vibronic coupling constants. The C-C stretching E-2g mode of 1668 cm(-1) plays an essential role in the electron-intramolecular-phonon coupling in the monoanion of coronene while the low frequency E-2 modes, which have a radial character, and the C-C stretching mode of 1669 cm(-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 sigma and pi 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-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(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 mu*=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 mu* is the Coulomb pseudopotential. The relationships between structures and T(c)s in alkali-doped A(3)C(60) complexes and graphite intercalation compounds (GICs) are also discussed from a viewpoint that corannulene can be viewed as a fragment of C-60 and coronene as a fragment of one-sheet graphite. (C) 2002 American Institute of Physics.