IMPROVED RESOLUTION IN HREELS USING MAXIMUM-ENTROPY DECONVOLUTION - CO ON PTXNI1-X(111)

High-resolution electron energy loss spectroscopy (HREELS) has been us ed to study stretch vibrations of CO chemisorbed at low coverage on Pt xNi1-x(lll). Bayesian probability theory along with the entropic prior (Maxent) has been employed to deconvolve the apparatus function and t o improve the apparent energy resolution. Maxent has proven very succe ssful in a wide range of inversion problems. Here the resolution enhan cement enables the positions of CO on the PtNi surface to be identifie d. It appears that CO is predominantly on top of Ni with the Ni atoms coordinated threefold laterally and with Ni in linear chains or on top of Pt. Furthermore, the ratio of the Pt to the Ni peak is used to stu dy the dependence of the Pt concentration in the first layer on the an nealing temperature.