Theoretical analysis of adsorbate structures on metal surface - Sodium atoms on tungsten /110/ plane

A theoretical analysis of the ordered structure of Na atoms adsorbed on the W(110) plane is carried out on the basis of the classical lattice gas model by use of the method of inequalities. It is shown that the characteristic patterns of ordering appear at specific value of the coverage. The condition for appearance of the observed ordering patterns and the possibility of finding new ordering patterns at coverage 1/7 and 1/5 are discussed. The order-disorder transition phenomenon is also discussed in the mean field approximation. The possibility of finding an intermediate phase at finite temperatures is suggested.