摘要
本文选取4,4′-二巯基联苯分子通过终端S原子化学吸附于两Au原子团簇形成分子结,利用从头计算方法和弹性散射格林函数理论研究了该分子两苯环之间不同位置取向对分子能级结构以及该分子结伏安特性的影响.计算结果表明苯环扭转角增加会使分子能级发生不同程度的移动,从而引起最高占据轨道(HOMO)与最低未占据轨道(LUMO)的间距增大.扭转角增大也会导致分子轨道的扩展性变差,从而使体系的导电性能降低.当扭转角为90度时,体系的导电性能最差.该工作有利于未来分子电子学器件的设计.
Basing on ab initio methods and the elastic scattering Green function method that we have developed, we investigate the molecular electronic structures and current-voltege characteristics of metalmolecule-metal junctions by varying the noncoplanar geometry of the two benzenes in the 4,4＇-biphenyldithiol molecule junction, where the molecule junction is formed through the end sulfur atoms chemically adsorbed on the two gold surfaces. The numerical results show that the change of the increase of the rotated angle between the two phenyl parts of the molecule can make the molecular levels slightly shift, which may lead to the increase of the gapbetween the highest-occupied-molecular-orbital （HOMO） and the lowest-unoccupied- molecular-orbital （LUMO）. The extensibilities of the molecular orbitals become worse with the increase of the rotated angle between the two benzene rings in 4,4＇-biphenyldithiol molecule, which can be expected to be negative for the flow of the electron across the interbenzene bonding region. There exists the poorest conductivity of the molecular system when one benzene ring becomes perpendicular m the other one. This work will be helpful for the design of the molecular electronic devices.
出处
《原子与分子物理学报》
CAS
CSCD
北大核心
2006年第3期587-590,共4页
Journal of Atomic and Molecular Physics
基金
国家自然科学基金(10274044)
山东省优秀中青年科学家科研奖励基金(03BS061)
关键词
分子电子学
伏安特性
杂化密度泛函理论
分子器件
Molecular electronics, current-voltage properties, hybrid density functional theory, molecular device
