Abstract
Recently, molecular dynamics simulations have predicted that when carbon dioxide gas enters a carbon nanotube, concentric layers of gaseous carbon dioxide molecules will appear. We show in this letter how this effect can be predicted analytically by considering the potential field generated by the pore wall. The layer potential expression thus derived can be used to reproduce the essential features of a particular MD study of gaseous carbon dioxide within a (40, 40) carbon nanotube and confirm, from an energetic point of view, that an outer gaseous layer will be stable. With a closed form expression for the layer potential known, we are able to derive formulas for quantities typically of interest in a Lennard-Jones analysis, such as minimum energy, equilibrium position and the location of zero potential.
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•Gaseous carbon dioxide layering in carbon nanotubes is described using an analytic model.•An outer gaseous layer, is demonstrated to be energetically favorable at room temperature.•A method to approximate the maximum pressure that can be inserted into the outer layer is given.•A method for estimating the dimensions of the outer gaseous layer is given.