Condensation effects in K-shell excitation spectra of neon films

Abstract

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-stimulated desorption of ${\mathrm{Ne}}^{+}$ , ${\mathrm{Ne}}^{2+}$ , and ${\mathrm{Ne}}_{2}^{+}$ as near-edge x-ray-absorption fine-structure probes with different surface sensitivities. From the comparison of these signals, we obtain excitation energies for excitonic and ionic surface and bulk states. The energy of the ${1\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$3p and ${1\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$4p surface excitation is different by 0.2 eV for the ${\mathrm{p}}_{\mathrm{z}}$ and the ${\mathrm{p}}_{\mathrm{xy}}$ symmetry. The ordering of the splitting depends on the principal quantum number.