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題  　目：　分子ワイヤーとその二量体における計算化学研究

Title   ：　Computational Chemistry Studies on Molecular 
            Wires and Diodes

発 表 者：　アハメド M. エルナハス
Speaker ：　Prof. Ahmed M. El-Nahas

所　  属　 ：  エル−ムヌーフィーヤ大学理学部化学科
Affiliation：  Chemistry Department, Faculty of Science, 
               El-Menoufia University, Shebin El-Kom, Egypt

日  　時：　 ４月７日（月）午後１時３０分〜（約１時間）
Date    ：　 Mon. Apr. 7th, 13:30 pm (Almost one hour)

場　  所： 　情報科学研究科３階演習室
Place   ：   3F Seminar Room, Graduate School of 
             Information Science

内　  容：
Abstract：
Recently, much attention has been paid to molecular ele-
ctronics to mimic the electronic function of silcon-based 
devices. In this respect, organic materials witnessed a 
great progress due to their promising electronic properties. 
Electrical conductivity of thiophene, pyrrole and furan 
has been intensively investigated. Assymmetric molecules 
(Diblock) are used as a molecular rectifier. The density 
functional theory calculations at B3LYP/6-31G(d) indicated 
that the insertion of nitrogen atoms in the conjugated 
backbone modifies the electronic structure of 
dipyrimidinyl-diphenyl (DPDPh) compared to its parent 
hydrocarbon and then affects its electrical properties. 
Consequently, the HOMO level of DPDPh under positive 
voltage became closer to the Fermi level of the electrode 
than it does under negative bias giving rise to a 
rectifying character. The HOMO?LUMO gap decreases steadily 
with increasing the number of nitrogen atoms, which would 
be used as a means for modifying the electrical properties 
in a regular mode. A significant reduction of the HOMO?LUMO 
energy gap (Eg), has been obtained with NHCH3 and OCH3 
substituted oligomers of phospholes.


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