Ground states of diatomic molecules adsorbed on single-walled carbon nanotubes

Abstract

We have studied the adsorption of diatomic molecules on graphite sheets and carbon nanotubes using Monte Carlo simulations. We have obtained the ground states for two-site dimer adsorption. On the high-coverage side, the ground states for dimer adsorption are highly degenerate. The complementary vacancy structures and the variation tendency of the ordered structures with increase of nanotube size are similar to those for single-site adsorption. On the low-coverage side, most dimer ordered structures are not degenerate. The confinement of nanotubes leads to helical ground-state structures for dimer adsorption.