Molecular dynamics simulations of H$_{\mathrm{2}}$O, NO$_{\mathrm{2}}$, and N$_{\mathrm{2\thinspace }}$mixtures on graphene.*

In this work we study the adsorption of mixtures of H$_{\mathrm{2}}$O, NO$_{\mathrm{2}}$, and N$_{\mathrm{2}}$ on graphene using the method of Molecular Dynamics. We run the simulations at constant temperatures from 100K to 230K. The H$_{\mathrm{2}}$O and NO$_{\mathrm{2}}$ molecules are modeled as a rigid 3-point systems and N$_{\mathrm{2}}$ is considered a spherical super-atom with Lenard-Jones interactions. The substrate is a rigid graphene layer located at the bottom of the simulation cell. The LJ parameters of interaction between the molecules and the graphene are calculated by fitting the atomistic pair-wise sum of carbon-atom interactions with the 9-3 potential. We calculate the selectivity of NO$_{\mathrm{2}}$/N$_{\mathrm{2}}$ and H$_{\mathrm{2}}$O/N$_{\mathrm{2\thinspace }}$on graphene to test the capability of graphene to separate nitrogen dioxide or water from air.