Calculation of Young's modulus of MoS$_{2}$-based single-wall nanotubes using force-field and hybrid density functional theory

A force field is proposed that reproduces with a high accuracy a large number of properties of the bulk crystal MoS$_{2}$ phases, monolayers, and nanotubes. The reproduced values are both the experimental results and the results of quantum chemical calculations. The elaborated interaction potential can be useful primarily for investigation of multiwall MoS$_{2}$ nanotubes and their thermodynamic properties, especially, since the potential is able to reproduce the frequencies of the crystal phonon spectrum. In this study the proposed potential is applied to simulate the temperature dependence of a number of properties of the armchair and zigzag nanotubes. The calculations have been performed using molecular mechanics method within the framework of quasi harmonic approximation which is carried out through the estimation of the temperature dependence of the Helmholtz free energy.