SIMS studies of adsorbate structure

Al97 Surface Science 117 (1982) 142-153 North-Holland Publishing Company

142

AUGER NEUTRALIZATION OF MULTIPLY IONS AT A TUNGSTEN SURFACE

CHARGED

NOBLE GAS

P. VARGA, W. HOFER and H. WINTER Institut fiir Allgemeine Received

Physik,

14 September

Technische

1981; accepted

Universitiit for publication

Wien, Austria 16 November

1981

Neutralization processes for slow doubly and triply charged noble gas ions impinging on clean polycrystalline tungsten are studied by observation of the resulting ejected electron energy distributions. A sequence of Auger de-excitation and Auger neutralization processes is demonstrated to occur and therefore strong evidence for participation of one-electron like transitions is information on the presented. In the special case of Ne 2+ impact this may yield straightforward density of states of the uppermost surface layer.

Surface Science 117( 1982) 154- 164 North-Holland Publishing Company

154

SIMS STUDIES

OF ADSORBATE

STRUCTURE

I. CO adsorption on Ru(OOl), Ni( 111) and Ni(100) A. BROWN and J.C. VICKERMAN Department Received

of Chemistry 14 September

UMIST, I98

Sackoille

1; accepted

Street, Manchester

for publication

M60 I QD, UK

24 November

198 I

The relationship between secondary ion intensities and adsorbate structure is explored by a comparison of experimental SIMS data for CO adsorption on Ni and Ru single crystals with corresponding literature data from techniques sensitive to the chemical structure of adsorbate complexes, i.e. LEED, IR and EELS. For all the surfaces studied, a correlation is established between the proportions of the secondary ions MCO+ and M,CO+ as a function of coverage and the fractional coverages of “bridge-bonded” and “linearly-bonded” CO as measured by the above techniques. These studies demonstrate that there is a clear and’accessible relationship between secondary ion emission and surface adsorbate structure. The parameters which influence this relationship will be discussed.

Surface Science 117 (1982) 165-168 North-Holland Publishing Company

165

SIMS STUDY OF THE INTERACTION WITH H, AND H,O S. BOURGEOIS

OF Ni-0

and M. PERDEREAU

FacuNP des Sciences Mirunde, Lcrborutoire de Recherches CNRS, B.P. 138, F-21004 Dijon Cedex, France Received

14 September

SURFACES

1981; accepted

for publication

sur la R&ctivitP

7 December

des Solides ussocih uu

1981

The interaction of oxygen with (001) and (I 11) Ni surfaces is studied mainly by static SIMS. The presence of OH groups on the surface is revealed. The reactivities of these Ni-0 surfaces and that of NiO(OO1) with respect of hydrogen and hydrogenated species are studied.