Interaction of vapours of mercury with PbS(001): a study by X-ray photoelectron spectroscopy, RHEED and X-ray absorption spectroscopy

Citation
F. Genin et al., Interaction of vapours of mercury with PbS(001): a study by X-ray photoelectron spectroscopy, RHEED and X-ray absorption spectroscopy, APPL SURF S, 173(1-2), 2001, pp. 44-53
Citations number
29
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
APPLIED SURFACE SCIENCE
ISSN journal
01694332 → ACNP
Volume
173
Issue
1-2
Year of publication
2001
Pages
44 - 53
Database
ISI
SICI code
0169-4332(20010322)173:1-2<44:IOVOMW>2.0.ZU;2-U
Abstract
The interactions of mercury on cleaved and polished galena PbS(0 0 1) were studied at room temperature. The surface of the samples was characterised b y X-ray photoelectron spectroscopy (XPS), RHEED and X-ray absorption spectr oscopy (EXAFS) before and after interaction with a pressure of 2.5 x 10(-3) mbar of mercury vapours. Sorbed mercury was oxidised to Hg(II), as reveale d by the chemical shift observed on the Hg 4f(7/2) levels. Since the adsorp tion of mercury is completely inhibited when the oxidation products of gale na cover the surface, the formation of Hg-S bonding is most likely to occur . The amount of adsorbed mercury at saturation was estimated to be about on e monolayer, i.e. one atom of mercury per surface atom of sulphur. A (I x 1 ) structure was observed by RHEED for the longest exposures. The analysis o f the EXAFS oscillations at the L-III edge of mercury allowed an estimate o f the Hg-S bond length of 2.62 Angstrom and a co-ordination number of 3. A model is proposed for the structure of the chemisorbed layer of mercury. (C ) 2001 Elsevier Science B.V. All rights reserved.