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This paper presents experimental data on the bonding of and NiO(100) and compares them with theoretical results. In the case of CO and NO on NiO(100) we find that the bonding energies obtained for the vacuum-cleaved single crystals agree well with results of recent studies on thin NiO(100) films grown by oxidation of Ni(100) whereas they are at variance with theoretical results. On the other hand, for CO on MgO(100) the experimental data fit well to recent theoretical studies while they contradict studies of adsorption on MgO(100) films grown on Mo(100). The experimentally determined values for the adsorption energies are 0.30 and 0.57 eV for adsorption of CO and NO on NiO(100), respectively, and 0.14 and 0.22 eV for adsorption on MgO(100). We suggest that the stronger bonding to NiO(100) as compared to MgO(100) is due to the influence of the 3d electrons of NiO.

Kinetic uptake data for xenon adsorbed onto large and uniform silicalite‐I crystals are presented over a temperature range of 121 K to 296 K. — Adsorption isotherms and corrected diffusion coefficients derived from the uptake curves are given. The heat of adsorption and activation energy of diffusion were estimated from the plots of reciprocal temperature against the logarithm of equilibrium pressure and corrected diffusion coefficients, respectively. — While the corrected diffusion coefficient is independent of coverage for the higher temperatures, it decreases significantly at the lower temperatures investigated (<170 K) when the limiting adsorption capacity has been reached. — Comparing the sorption diffusion data with self‐diffusion coefficients obtained by NMR‐pulsed field gradient techniques, the room‐temperature mobility of xenon in silicalite‐I derived from sorption measurements is lowered by one order of magnitude. However, this result should not be considered necessarily as a discrepancy, due to uncertainties inherent in both techniques.

Literatur 111 Karge, H. G . ; hniecki, M.; Ziolek, M.; Onyestya'k, G.; Kiss, A , ; Kleinschmit, I?; Siray, M.: