Structure and melting of submonolayer ethane films on graphite

Abstract

URL:http://link.aps.org/doi/10.1103/PhysRevLett.43.1878 DOI:10.1103/PhysRevLett.43.1878Elastic 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.We acknowledge partial support of this research by the National Science Foundation under Grant No. DMR-7905958, the NATO Research Grants Program, the Petroleum Research Fund administered by the Amnerican Chemical Society, a Dow Chemical Company Grant of the Research Corporation, the University of Missouri Research Concil, and the University of Missouri Research Reactor Facility. One of us (G.J.T.) is in receipt of an American Chemical Society - Petroleum Research Fund Fellowship