Monte Carlo study of multicomponent monolayer adsorption on square lattices

G.D.GARCIA; F.O.SANCHEZ-VARRETI; F.M. BULNES; A. J. RAMIREZ-PASTOR

SURFACE SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2010

0039-6028

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:14.0pt; mso-bidi-font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; color:navy;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The monolayer adsorption process of interacting binary mixtures of species A and B on square lattices is studied through grand canonical Monte Carlo simulation in the framework of the lattices gas model. Four differente energies have been considered in the adsorption process: 1) e0, interaction energy between a particle (type A or B) and the lattice site; 2) wAA, interaction energy between two nearest-neighbor A particles; 3) wBB, interaction energy between two nearest-neighbor B particles; 4) wAB=wBA, interaction energy between two nearest-neighbors being one of type A and the other of type B. The adsorption process has been monitored through total and partial isotherms and differential heats of adsorption corresponding to both species of the mixture.  Our main interest is in the repulsive lateral interactions where a variety of structural orderings arise in the adlayer, depending on the interaction parameters (wAA, wBB and wAB). At the en of this work, we determine tha phase diagram characterizing the phase transitions occurring in the system. A nontrivial interdependence between the partial surface coverage of both species is observed.