The kinetics of Rh inter-diffusion into a Pt(100) surface was investig
ated on abrupt interfaces of Rh/Pt(100) which were artificially create
d by thermal evaporation of 0.8 and 1.5 monolayers of Rh on a (5 x 20)
reconstructed Pt(100) substrate at 110 K. Deposition of a small amoun
t of Rh on a clean and reconstructed Pt(100) surface destroys the reco
nstruction and yields a (1 x 1) structure. The kinetics of Rh diffusio
n from the overlayer into the bulk was monitored by Auger electron int
ensities of the Rh and Pt signals as a function of time and annealing
temperature. The activation energies of inter-diffusion are derived to
be 1.63 +/- 0.4 and 1.68 +/- 0.2 eV for 0.8 and 1.5 monolayer coverag
es, respectively.