The Nature of the Melting Transition for a Mixed Monolayer System Physisorbed onto Graphite: Argon and Krypton Patch Impurities

Monolayer System Physisorbed onto Graphite: Argon and Krypton Patch Impurities M. W. Roth Department of Natural Sciences, Texas A&M International University, 5201 University Boulevard, Laredo, Texas 78041 Received February 10, 1998. In Final Form: December 24, 1998 A constant density (F ) 1) constant temperature molecular dynamics method with periodic boundary conditions is utilized to examine the melting transition for argon impurity patches embedded in krypton monolayer matrixes (as well as for the complement system) deposited onto graphite for various values of argon impurity fraction X. The character and temperature Tm of melting are found to be dependent on the impurity fraction as well as adsorbate topology vis-à-vis which species is the patch impurity andwhich is thematrix. No phase separation is observed, as themelting temperature of thematrix is coincident with that of the patch in all cases examined. Much of the behavior exhibited by the system in this study can be understood by vacancy formation arguments.