1University Department of Physics, B.R.A. Bihar University, Muzaffarpur, BIHAR, INDIA.
2Dept. of Physics, Samta College, Janadaha, Vaishali, BIHAR, INDIA.
3H.N.K. Inter College, Ara, BIHAR, INDIA.
4Dept. of Physics, Samta College, Janadaha, Vaishali, BIHAR, INDIA.
5Dept. of Chemistry, Samta College, Janadaha, Vaishali, BIHAR, INDIA.
We have studied phonon dispersion of an isolated linear chain of carbon atoms. We have obtained from the analysis of oligomers that for any real conjugation length determined by the size of polygne chain. In finite chain with a given degree of conjugation are associated with a given bond length alternation. Bond length alternation modulated the effect of electron phonon coupling responsible of the softening of active carbon chains stretching mode. Our results shed light on polygnic system indicating strong analogies with other carbon polyconjugated systems sharing the same Physics of the Kohn anomaly. We have used density functional theory for this purpose.
Phonon dispersion, carbon atoms, electron phonon coupling
