On the commensurate-incommensurate transition in adsorbed monolayers

A Monte Carlo simulation method is used to study the commensurate-incommens urate phase transition in monolayers and the formation of bilayer films on the (100) face of an fee crystal. The phase diagram for the system which fo rms the registered(1x1)and high density incommensurate phases in the monola yer has been determined. It is shown that the registered phase undergoes th e transition to a denser incommensurate solid phase when the film density i ncreases. The mechanism of melting of the monolayer film is found to depend on the film density. In particular, the melting of dense incommensurate so lid monolayer film is found to be accompanied by the transfer of adsorbed m olecules into the second layer. (C) 1999 Published by Elsevier Science B.V. All rights reserved.