EXTRACTION OF INELASTIC MEAN FREE-PATH DATA FROM ELASTIC ELECTRON BACKSCATTERING DATA

The possible extraction of inelastic mean free path (IMFP or lambda(i) ) data from elastic backscattering experiments is analyzed within the transport approximation. It is found that the characteristic length ob tained by this method is not the IMFP, lambda(i), as previously though t, but a length LAMBDA = [lambda(i)-1 + lambda(tr)-1)]-1/2, where lamb da(tr), the transport mean free path, is the length associated with la rge-angle deflection. It is significant that this length LAMBDA is als o the length which characterizes the overlayer experiment for an ultra thin overlayer (thickness much-less-than IMFP) and at an exit angle of approximately 45-degrees, and is also the length obtained using two-s tream methods [V. M. Dwyer, Surf. Sci. 291, 261 (1993)].