Investigation on the Frequencies of Radial breathing mode and Radial breathing-like mode of Carbon nanotubes

Carbon nanotubes (CNTs), one of the important symbol to enter the era of nanotechnology, becomes the most attractive materials with the unique properties, and CNTs shows extensive potential application in drug molecular transmission, CNTs tip and CNTs-based sensors. However, the application of nano-device requires more accurate research about geometric, electronic and mechanical properties which matches to radial breathing vibrational mode in Raman spectroscopy experiment. The shapes and frequencies of radial breathing mode(RBM) and radial breathing-like mode(RBM-like) were investigated by the modified beam element model based on molecular mechanics, and the relationship of frequencies of zigzag and armchair CNTs with length - diameter aspect ratio, diameter and chirality were also discussed respectively. The results show that there are RBM and RBM-like in radial vibration of CNTs, and their frequencies are approximate.