Acoustic phonon spectrum of unaligned multi-walled carbon nanotubes and zero phonon Rayleigh Mossbauer scattering

作者：Silotia P^*; Dabas S; Saxena A; Tewari S P

来源：Indian Journal of Physics and Proceedings of the Indian Association for the Cultivation of Science, 2015, 89(5): 417-423.

DOI：10.1007/s12648-014-0607-2

• Specific heat
• Multi-walled carbon nanotubes
• Frequency distribution function
• Rayleigh Mossbauer recoilless scattering fraction

Frequency distribution function of acoustic phonons in unaligned multi-walled carbon nanotubes has been obtained, for the first time, by unfolding experimentally measured temperature variation of its specific heat in the range of 1-200 K. We have used a dynamical model that not only takes into account surface modes of the graphene sheets that form carbon nanotubes, but also inter-tube coupling through the presence of three-dimensional modes. The unfolded frequency distribution function of dynamical modes yields temperature dependent specific heat that is in good agreement with corresponding experimental results-in most of the temperature range, deviation is similar to 5 % or less. The computed temperature dependent values of zero phonon Rayleigh Mossbauer scattering fraction of Sn-119 gamma-photons have been obtained by using the suggested dynamical model and the final unfolded frequency distribution function. It turns out that zero phonon Rayleigh Mossbauer scattering fraction varies with temperature markedly and can be rather easily measured.

• 出版日期2015-5