All-atom Molecular Dynamics simulations of partial pentane and hexane films on graphite*

We compare the self-assembly patterns of pentane (C$_{5}$H$_{12})$ and hexane (C$_{6}$H$_{14})$ adlayers physisorbed onto graphite at various coverages using the results of molecular dynamics simulations. Near monolayer coverage, the solid low temperature structure of the pentane film is nematic-like, and that of hexane-herringbone-like. At submonolayer coverages both systems exhibit three distinct topological regimes: vacancy patches at higher densities, percolating networks at intermediate densities and ultimately individual patches. The systems' orientational behavior and melting dynamics is discussed with respect to its unique density-dependent topology. The simulations explicitly include hydrogens of pentane and hexane and the graphite is modeled as a six-layer all atom structure.