Preferred orientations of encapsulated C60 molecules inside single wall carbon nanotubes

摘要

A systematical study of the orientational bchavior of C60 molecules in single wall carbon nanotubes (SWCNTs) with different chirality and diameter has been performed by using a model of an infinite long nanotube filled with two C60 (denoted as C60-1 and C60-2) molecules.We studied the preferred orientation of the C60-1 molecule when the neighboring C60-2 molecule was fixed at the pentagon,double-bond,and hexagon orientations respectively.Our results showed that the C60-1 molecule prefers the pentagon (hexagon) orientation when the tube diameter is smaller (larger) than 1.31 nm (1.36 nm).For the tube diameter in between,the preferred molecular orientation of C60-1 changes from pentagon to hexagon with the increasing tube diameter when the neighboring C60-2 molecule is fixed at the pentagon or double-bond orientation.A novel vertex orientation for the C60-1 molecule has been found when the C60-2 molecule is fixed at the hexagon orientation.