STRUCTURAL-PROPERTIES OF NA ADSORBED ON A GE(100)2X1 SURFACE - ALL-ELECTRON, AB-INITIO, DENSITY-FUNCTIONAL, CLUSTER CALCULATIONS

We present the first theoretical investigation of the structural prope rties of the Na/Ge(100)2 x 1 system, The binding of a single Na atom a t different possible adsorption sites on the Ge(100)2 x 1 surface was studied using DMol, an all electron, ab initio local density functiona l duster method, In contrast to our previous results for the Na/Si(100 )2 x 1 system, we find the pedestal site to have the lowest total ener gy. This situation differs from the Si(100)2 x 1 surface where Na atom s were found to adsorb preferentially on the cave site, Furthermore Na atoms, when covalently bonded to the Ge dangling bonds tend to symmet rize the Ge dimer.