We report on a high energy resolution X-ray photoelectron spectroscopy plus supersonic molecular beam investigation of O/Ag(210). Two components are detected in the O1s spectra upon O-2 adsorption, at binding energies E-B =527.7 and 529.6 eV. The former peak persists up to 470 K, while the latter one decreases abruptly above 280 K. Comparison with a previous vibrational spectroscopy investigation on the same system (L. Vattuone, et al. Phys. Rev. Lett. 2003, 90, 228302) allows to assign both features to atomic oxygen. The low-energy peak is identified with adatoms, while the other is correlated to O atoms in subsurface sites. A minor contribution at the same binding energy, due to carbonates, is quantified by inspection of the C1s region and shows a different temperature behavior with respect to oxygen. Oxygen segregation into the subsurface region is observed when heating the crystal in the presence of supersurface oxygen.
Monitoring super- and subsurface oxygen on Ag(210) by high energy resolution X-ray photoelectron spectroscopy: Subsurface diffusion and segregation
Savio L;Gerbi A;Vattuone L;Baraldi A;
2006
Abstract
We report on a high energy resolution X-ray photoelectron spectroscopy plus supersonic molecular beam investigation of O/Ag(210). Two components are detected in the O1s spectra upon O-2 adsorption, at binding energies E-B =527.7 and 529.6 eV. The former peak persists up to 470 K, while the latter one decreases abruptly above 280 K. Comparison with a previous vibrational spectroscopy investigation on the same system (L. Vattuone, et al. Phys. Rev. Lett. 2003, 90, 228302) allows to assign both features to atomic oxygen. The low-energy peak is identified with adatoms, while the other is correlated to O atoms in subsurface sites. A minor contribution at the same binding energy, due to carbonates, is quantified by inspection of the C1s region and shows a different temperature behavior with respect to oxygen. Oxygen segregation into the subsurface region is observed when heating the crystal in the presence of supersurface oxygen.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
