Single walled carbon nanotubes (SWCNT) can encapsulate small and large molecules, including fullerenes [1-4]. C60 peapods consist of SWCNT in which C60 fullerene molecules are inserted. This hybrid system between C60 fullerene and SWCNT have generated a lot of interest for future electronic applications. Carbon peapods have been proposed as possible candidates for novel nanometer scale devices and many efforts led to the synthesis of high-quality 1D fullerene crystals inside SWCNTs [1, 4]. Due to their original one-dimensional nanosized structure and their tunable electronic properties, peapods have several potential applications as high temperature superconductors [5], memory elements [6] and nanometer-sized containers for chemical reactions [3].

In contrast to theoretical considerations, the experimental verifications of the CNTs strength or Young's modulus demonstrate evidently discrepancies that may

reach even up to 30% [7]. Structural defects in nanotubes have been identified by STM and HRTEM imaging [8, 9]. Possible single or multiple defects in CNTs provide an explanation for the extant theoretical experimental differences.

The purpose of the current study is to investigate the effect of C60 fullerene confined inside defective carbon nanotubes on vibrational properties of peapod, in this aim we use a spectral moment method together with a bond polarizability model. Essentially, the vibrational properties are closely coupled with the atomic structure of the system. The evolution of the Raman spectrum as a function of the spatial arrangement of defects in carbon nanotubes is discussed. The changes of the Raman spectrum as a function of the filling factor is identified. 

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