THE WORK FUNCTION CALCULATIONS FOR W(100)-Cs ADSORBED SYSTEMS BYJELLIUM ON ATOMIC SLAB MODEL

The work functions of transition metals vary drastically wirh the coverage of adsorbed alkali or alkaline earth metal atoms. This phenomenon is studied theoretically by a refined model, i.e., the transition-metal substrate is treated whh high accuracy by the film LAPW method, while the simple metal overlayer is simulated by the jellium model. Computation of the electronic structure of the adsorbed system with a coverage of lower than monolayer will become possible by using this model. The variations of work function () with the converage () of Cs on the W-substrate are presemted. the calculated min=1.441.48eV is in goood agreement with the experimental value (1.351.55eV). The close dependance of the results on the choice of parameter, Ev, is also discussed.