Vibrational dynamics and heat capacity of poly(l-ornithine)

Abstract

The normal modes and their dispersions for poly(l-ornithine) in the unusual cross-β form have been obtained in the reduced zone scheme using Wilson's GF matrix method as modified by Higgs. Optically active frequencies corresponding to the zone center and zone boundary are identified and discussed. Some of the characteristic features of the dispersion curves are repulsion accompanied by an exchange of character and von Hove type singularities. Heat capacity has been calculated via density-of-states using Debye's equation in the temperature range 50–500K.

Keywords:

• Poly(l-ornithine)
• Phonon dispersion
• Repulsion
• Density-of-states
• Heat capacity

Acknowledgments

Financial assistance to Sapna Pande (under the Junior Research Fellowship Scheme) from the Council of Scientific and Industrial Research, New Delhi, and to Poonam Tandon from the Department of Science and Technology, New Delhi, and Mr. Rajesh Khanna, C.D.R.I., Lucknow, for running the spectra are gratefully acknowledged.