Structure of CF 4 multilayers on (0 0 0 1) surfaces of graphite and hydroxylated α -quartz: A molecular dynamics study

• Published in: Surface science Vol. 603; no. 23; pp. 3374 - 3381
• Main Authors: Leuty, Gary, Nehring, Jonathan, Tsige, Mesfin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2009
• Subjects: Computer simulations; Molecular dynamics; Physical adsorption; Silicon oxides; Surface structure; Computer simulations; Silicon oxides; Molecular dynamics; Physical adsorption; Surface structure
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2009.09.030

We present findings from a recent molecular dynamics study of multilayer adsorption of tetrafluoromethane ( CF 4 ) onto two atomically flat but chemically and structurally different substrates: graphite (hydrophobic) and hydroxylated α -quartz (hydrophilic). Simulations in this study were carried out at temperatures in the range of 60–120 K. Subsequent analysis shows that the structure and character of the substrate surface play a large role in whether adsorbed films exhibit packing arrangements that are highly ordered or are subject to a high degree of temperature dependence. Additionally, flexible hydroxyl groups on the surface of hydroxylated α -quartz are shown to arrange themselves in a zig-zag pattern that creates an array of hexagonal domains which determine the allowed CF 4 adsorption sites.