A DF T study on structu ral proper ties of phenyl-capped oligoth iophenes

One of important s tructural fa ctors relate d to the extention of the ʌ-conjugation of a polymeric system is the chain planarity which can be reflect by the tortional angles an d alternatio n of single and doubl bonds alo ng the polymer chain which can be indicate b y bond alt ernation parameter or quinoid para meter. In this work, we investigate the structural properties for some oligothio phenes with and without phenyl-capped group using DFT calculati ons. Effecti ve dihedral angles, bonds length of carbon backbone in π-conjugate d system, b ond alternation parameter and quinoid parameter is obtain ed in this wo rk. Computational methodes: Density functional theory (DF T) [۱] as implemented in Gaussia n ۰۹ program has be en employed to optimize the geome try of oligomers. The geometry optimizations a re carried out at the B ۳LYP/۶-۳۱G (d,p) level of theory w ithout sym metry restri ction for ne utral, cationic and anionic species of each oligomer.

کلیدواژه ها:

DFT ، Structural properties ، Phenyl-capped ، Oligothioph enes