Structure and Melting of Submonolayer Ethane Films on Graphite

Abstract

Elastic neutron diffraction has been used to study the structure and melting of submonolayer ethane films physisorbed on exfoliated graphite. Analysis of the relative intensity of seven Bragg reflections of the film yields the molecular orientation in the close-packed solid structure observed below 63 K. At higher temperature a novel melting process occurs which we tentatively interpret as a first-order transition to an intermediate phase followed by continuous transition to the disordered state.