Sharp photon-induced np→(n+1)s resonances in Xe and Kr monolayers observed by spin-resolved electron spectroscopy

Abstract
Narrow Xe 5p→6s and Kr 4p→5s resonances (ΔE meV) have been observed in the adsorbate phase on Pt(111) and graphite (0001). The photon-induced transitions reveal an additional level splitting compared to the gas phase and the intensities show a significant substrate dependence. The resonances were detected via spectroscopy of the electrons emitted due to a subsequent relaxation decay of the excited state. Measurement of the electron-spin polarization clarified the nature of the new decay mechanism observed and furthermore provided an unambiguous quantum-number labeling of the resonances.