Experimental resolution of surface and bulk atoms in ligated metal clusters

1 Experimental resolution of surface and bulk atoms in ligated metal clusters 

When the electron-escape angle, measured relative to the plane of the graphite substrate, is reduced, a shift towards higher BE and a broadening of Au 4f peak are observed. The line shape is asymmetric. Both effects can be caused by a relative enhancement of the component from Au surface atoms. By taking linear combinations of the 10° and 90° spectra, denoted P(10°) and P(90°), the surface contribution to the Au 4f spectrum [S) is separated in Fig. 3 from the contribution of the deeper lying Au atoms (B), because S is proportional to [P(10°) - 7P(90°)] and B to [P(90°) - P(10°)]. 

B and S were fitted to a line shape consisting of a mixture of a Gaussian and a Lorentzian. 

From the spectra at five different photoelectron collection angles, the linear combinations for both B and S components yield a consistent set of values of shape, width, and The small variation of these values and the symmetry of the 

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