LEED AND THE EFFECTIVE SURFACE DIPOLE-MOMENT OF NI(111)-P(2X2)K

In most of the low-energy electron diffraction (LEED) studies Of the g eometric structure of alkali metals on metal surfaces, the level of ag reement between experimental and theoretical intensity-energy curves h as been relatively low. It has been proposed [1] that the origin of th e low level of agreement is due to the induced dipole potential at the position of the adatom, and that the agreement between the experiment al and theoretical curves can be improved by the inclusion of a point dipole potential in the LEED calculations. Such improvement was demons trated for the case of K/Ni(100) [1]. In this paper, we show that incl usion of a point dipole in the calculated potential does not improve t he level of agreement in the case of Ni(111)-p(2 x 2)K.