The relative abundances, relative dipole moments, and absolute sticking coefficients of virgin, alpha, and beta CO adsorbed on tungsten have been determined by a combination of work function vs coverage measurements with stephyphen;desorption spectra and stickinghyphen;coefficient measurements. The workhyphen;function data were obtained in a fieldhyphen;emission tube with an annular CO source, permitting uniform dosing of the tip. The other measurements were performed in a tube in which a CO source illuminated a tungsten ribbon. A movable field emitter serving as detector could be raised in front of this ribbon to receive CO from the latter in desorption or reflection. This arrangement represents a new method of determining sticking coefficients, free from the ambiguities of surface roughness and wall adhyphen; or desorption, usable to 20deg;K or less.The dipolehyphen;moment ratios werePagr;/Pv= minus;0.68;Pbgr;/Pv= 0.68 for the initial, andPbgr;/Pv= 1.0 for the terminal portion of the beta layer. The relative abundances were total beta/total virgin = 0.55; virgin converted to beta/beta from virgin conversion = 2.1; alpha/total beta = 1.2.Initial sticking coefficients were close to unity up to 700deg;K, and decreased rapidly at coverages (relative to the maximum amount of adsorbate retained at that temperature) of 0.6ndash;0.4.
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