An FTIR spectroscopic study of the adsorption of natural and lSO-enriched CO:! gases on MgO powders was performed and was compared with temperature-programmed desorption analysis. Two types of COS species (a and b) were found after Cl60z adsorption at room temperature: they have characteristic wavenumbers 1659, 1329, and 1024 cm-' (type a) and 1626, 1273, and 947 cm-l (type b), respectively. Ab initio molecular orbital calculations gave theoretical wave numbers. According to comparison of these numbers, type b is a monodentate model. Type a could not be reproduced in the present limited cluster model. It is inferred that it also comes from a monodentate model with partly bidentate and "tridentate" characters.

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The adsorbability of the Langmuir-Blodgett (LB) film of octadecylamine (ODA) has been investigated using R-naphthol orange (NO) and methyl orange (MO) as adsorbates. It was found that the specific adsorptions of these azo dyes occurred on the ODA LB film predominantly by ionic interaction, and also that the adsorption behavior depended on pH according to the ionic states of NO and MO as well as that of the ODA LB film. The structural characteristics of the LB films such as orientation, layer-layer distance, and topography of the film surface have been evaluated by means of FTIR and UV-vis spectroscopies, X-ray diffraction in the low-angle region, and atomic force microscopy (AFM), respectively. The results obtained indicated that the adsorption of dyes induced rearrangements of the layer structure, where the hydrocarbon chains took an interdigitated structure and the dye molecules in the LB film exhibited remarkable distinction in the adsorbing state, i.e., a lie-flat configuration of NO and an edge-on configuration of MO.

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