ANHARMONIC EFFECT ON ORIENTATIONAL ORDERING IN ADSORBED INCOMMENSURATE MONOLAYERS

The orientational ordering in adsorbed incommensurate monolayers is discussed in an anharmonic approach. A nonlinear relationship is predicted between the orientation of the monolayer relative to the substrate and the monolayer lattice parameter. Calculated values of the rninimum energy crientation angle for Ar on graphite are in good agreement with the experimental reported measurements.