CONDENSATION EFFECTS IN K-SHELL EXCITATION-SPECTRA OF NEON FILMS

Using synchrotron radiation under high-resolution conditions, we have investigated the excitation of electronic states at the K edge in neon multilayers. In addition to the electron yield, we use photon-stimula ted desorption of Ne+, Ne2+, and Ne-2(+) as near-edge x-ray-absorption fine-structure probes with different surface sensitivities. From the comparison of these signals, we obtain excitation energies for exciton ic and ionic surface and bulk states. The energy of the 1s(-1)3p and 1 s(-1)4p surface excitation is different by 0.2 eV for the p(z) and the p(xy) symmetry. The ordering of the splitting depends on the principa l quantum number.