Influence of Carbon Curvature on Molecular Adsorptions in Carbon-Based Materials: A Force Field Approach

A general force field methodology is developed for description of molecular interactions in carbon-based materials. The method makes use of existing parameters of potential functions developed for $s{p}^2$ and $s{p}^3$ carbons and allows accurate representation of molecular forces in curved carbon environment. The potential parameters are explicitly curvature and site dependent. The proposed force field approach was used in molecular dynamics (MD) simulations for hydrogen adsorption in single-walled carbon nanotubes (SWNTs). The results reveal significant nanotube deformations and the calculated energies of adsorption are comparable to the reported experimental heat of adsorption for ${\mathrm{H}}_2$ in SWNTs.

Figure 1

Radial distribution functions for exohedral ${\mathrm{H}}_2$ over the 100 000 steps of the 100 ps MD simulation.