A79 Surface Science 151 (1985) 251-259 251 North-Holland, Amsterdam FORMATION OF N3+ IN PULSED-LASER STIMULATED FIELD DESORPTION OF NITROGEN FROM METAL SURFACES W. LIU * and T.T. TSONG Physics Department, The Pennsylvania State University, University Park, Pennsylvania 16802, USA Received 30 May 1984; accepted for publication 31 August 1984 in pulsed-laser stimulated field desorption of nitrogen from metal surfaces, a plenty of Nf can be detected. Here we present the result of a study of the field dependence and emitter material specificity 01 N3 + formation in pulsed-laser stimulated field desorption, These ions are formed by field ionization of N 3 molecules which are thermally desorbed from their field adsorption states by laser pulse heating of the surface. 260 Surface Science 151 (1985) 260-270 North-Holland, Amsterdam VIBRATIONAL CHARACTERIZATION OF CARBON MONOXIDE OXIDATION ON THE Pt(lll) SURFACE John L. GLAND * and Edward B. KOLLIN * Physical Chemistry Department, General Motors Research Laboratories, Warren, Michigan 48090, USA Received 27 March 1984; accepted for publication 11 July 1984 The surface reaction between coadsorbed carbon monoxide and atomic oxygen has been characterized using high resolution electron energy loss spectroscopy, coupled with temperature programmed reaction spectroscopy on a Pt(lll) surface characterized using Auger electron spectroscopy and low energy electron diffraction. Preferential oxidation of bridge bonded CO is not observed despite the fact that bridge bonded CO is adsorbed less vigorously than linearly bound CO. Saturation of the Pt(lll) surface with one quarter of a monolayer of atomic oxygen completely suppresses the adsorption of bridge bonded CO. However, substantial coverages of bridge bonded CO can be coadsorbed if the Pt(111) surface is only partially saturated with atomic oxygen. The vibrational data for reaction of coadsorbed CO and atomic oxygen is consistent with a reaction mechanism involving reaction of mobile CO along oxygen island perimeters. Surface Science 151 (1985) 271-288 271 North-Holland, Amsterdam ADSORPTION AND REACTION OF BROMINE WITH Ag(ll0) Carsten BENNDORF and Bernd KRISGER Department of Physical Chemistry, University of Hamburg, D-2000 Hamburg 13, Fed. Rep. of German)' Received 19 July 1984, accepted for publication 26 October 1984 The adsorption and reaction of Br2 with Ag(110) was studied with Auger electron spectroscopy, LEED, work function measurements and thermal desorption spectroscopy in the temperature range of 130-1000 K. Depending on Br coverage and crystal temperature, four different adsorp-