ESR AND TPD INVESTIGATIONS OF THE ADSORPTION OF DI-TERT-BUTYL NITROXIDE ON AU(111) AND NIO(111) - EVIDENCE FOR LONG-RANGE INTERACTIONS

Electron spin resonance and temperature-programmed desorption spectra of thin layers of DTBN (di-tert-butyl nitroxide) adsorbed on Au(111) a nd NiO(111)/Au(111) surfaces have been measured. The temperature-progr ammed desorption data show a weak chemisorption of the DTBN molecules in the monolayer on both surfaces. On Au(111) as well as on NiO(111)/A u(111), the ESR signal from monolayer coverages is totally suppressed. This suppression continues into the multilayer regime on both substra tes. Disturbances of the substrate/adsorbate interface have a strong i nfluence on the range of the signal suppression. Possible reasons for this behavior are discussed. (C) 1997 Academic Press.