INFLUENCE OF THE ADSORBED LAYER RANDOMNESS ON CHARGE-TRANSFER IN ALKALI-METAL ADSORPTION ON METAL-SURFACES

We investigate theoretically the effects of the adlayer randomness at low coverages on the charge state of alkali adatoms within the Muscat-Newns model [Solid State Commun. 11, 737 (1972)]. The fluctuating electrostatic potential at an adatom site due to a random arrangement of all the other atoms in the adlayer is modeled in analogy to Holtsmark's theory of static broadening of spectral lines in plasmas. We find that these fluctuations induce a stronger depolarization of the adlayer with increasing coverage than in the Muscat-Newns model, corresponding to a slower drop of the effective work function. © 1994 The American Physical Society.