Advanced molecular structural mechanics model for carbon nanotubes incorporating the 2nd generation REBO potential

Abstract

Molecular mechanics models like the molecular structural mechanics (MSM) model have been proven to be a valuable tool for the investigation of carbon nanotubes. This class of models is based on a chemical force field representing the bonds present in the structure. Up to now, the underlying chemical force field applied in the MSM model is usually based on harmonic potentials. This simple approach comes with major drawbacks limiting the abilities of the MSM approach. In order to overcome these limitations, the present work integrates the 2nd generation reactive bond order potential (REBO), which is a sophisticated chemical force field, into the MSM approach. The development of this advanced MSM model is given in detail. As a demonstration of its capabilities, the elastic properties of different armchair and zig-zag CNTs are investigated numerically. It was found, that the results for the elastic properties differ significantly with the choice of the underlying chemical force field. The arising differences are discussed and reasons for the occurring behavior are given. The developed advanced MSM approach on the basis of the REBO potential strongly enhances the capabilities of the MSM approach while maintaining its excellent accessibility and applicability together with a low computational effort.