Electron-phonon coupling in negatively charged acene- and phenanthrene-edge-type hydrocarbon crystals
Electron-phonon coupling in negatively charged acene- and phenanthrene-edge-type hydrocarbon crystals
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DOI：
10.1063/1.1445102
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发表时间：
2002-02-22
影响因子：
4.4
通讯作者：
Hirao, K
中科院分区：
文献类型：
--
作者：
Kato, T;Yoshizawa, K;Hirao, K
本文研究了菲-边型芳烃单阴离子的振动相互作用及其在超导电性发生中的作用。计算并分析了振动频率和电子振动耦合常数，估算了电子-声子耦合常数。并将菲边型烃的计算结果与并苯边型烃的计算结果进行了比较。并苯和菲边型碳氢化合物单阴离子的最低频率模和1400-1600 cm（-1）的C-C伸缩模具有较大的电子-声子耦合常数。总的电子-声子耦合常数随并苯-和菲-边型烃中碳原子数的增加而减小，但菲-边型烃的单阴离子的耦合常数大于并苯-边型烃的单阴离子的耦合常数.估计了一元阴离子可能的超导转变温度T（c）s。如果菲边型烃具有超导电性，菲边型烃的单阴离子将比并苯边型烃的单阴离子具有更高的T（c）s。这些结果表明，分子的边缘结构以及分子的大小与电子-声子耦合的强度和T（c）s有关。采用碎片分子轨道方法（FMO）成功地表征了蒽和菲两种不同边缘的多环芳烃（PAHs）的电子结构。(C)2002年美国物理学会。
Vibronic interaction and its role in the occurrence of possible superconductivity in the monoanions of phenanthrene-edge-type aromatic hydrocarbons are studied. The vibrational frequencies and the vibronic coupling constants are computed and analyzed and the electron-phonon coupling constants are estimated. The results for phenanthrene-edge-type hydrocarbons are compared with those for acene-edge-type hydrocarbons. The lowest frequency mode and the C-C stretching modes of 1400-1600 cm(-1) afford large electron-phonon coupling constants in the monoanions of acene- and phenanthrene-edge-type hydrocarbons. The total electron-phonon coupling constants decrease with an increase in the number of carbon atoms in both acene- and phenanthrene-edge-type hydrocarbons, but those for the monoanions of phenanthrene-edge-type hydrocarbons are larger than those for the monoanions of acene-edge-type hydrocarbons. Possible superconducting transition temperatures T(c)s for the monoanions are estimated. The monoanions of phenanthrene-edge-type hydrocarbons would have higher T(c)s than the monoanions of acene-edge- type hydrocarbons if phenanthrene-edge-type hydrocarbons exhibit superconductivity. These results suggest that molecular edge structures as well as molecular sizes have relevance to the strength of electron-phonon coupling and T(c)s. The fragment molecular-orbital method (FMO) method successfully characterizes the distinct electronic structures of the two small polynuclear aromatic hydrocarbons (PAHs) with different type of edges such as anthracene and phenanthrene. (C) 2002 American Institute of Physics.