Core-excited Ne∗(1s−1nℓ) states on a Ne surface

When a core-excited Ne∗(1s−1nℓ) atom is formed surrounded by other Ne atoms, the excited orbital interacts with the surrounding dielectric medium. This problem is studied for Ne∗(1s−1nℓ) atoms located at the surface of a Ne crystal using a microscopic description of the Ne surface that incorporates the dielectric character of the Ne crystal. The environment-induced modifications of the excited orbital can be qualitatively described in terms of confinement and polarization effects. The vacuum/crystal asymmetry in the environment of the excited orbital leads to a considerable asymmetry of the excited orbital in particular for high lying states. Though the lowest lying 3s and 3p states mostly retain their atomic character. Higher lying states are much hybridized and cannot be assigned to a single atomic orbital. The present results compare very well with available experimental data. They lead to a reassignment of the various peaks in the excitation spectra of Wiethoff et al. [P. Wiethoff, H.-U. Ehrke, B. Kassühlke, C. Keller, W. Wurth, D. Menzel, P. Feulner, Phys. Rev. B 55 (1997) 9387].