No abstract

No abstract

The interaction of iron atoms with oxygen molecules and atoms in an argon matrix over the temperature range from 15 to 40 K has been examined. The iron atoms are produced by a hollow-cathode sputtering device. Iron-oxygen complexes are identified by oxygen-18 isotope shifts in the infrared spectra, annealing behavior, and comparison to known compounds. A band at 956 cm-' is assigned to the 0-0 stretching frequency of a side-bonded FeOt structure, an assignment at variance with current literature. A band at 872 cm-l is assigned to FeO while a band at 969 cm-' is assigned to an Fe-O stretching mode of linear 0-Fe-O. A band at 946 cm-l is tentatively assigned to metastable bent 0-Fe-O species which disappears upon annealing the matrix at 25 K. Oxygen atoms are formed on the surface of the matrix during its formation by the reaction of O2 molecules with excited argon atoms from the hollow-cathode discharge. The verification of the existence of a stable Fe02 complex which still contains an 0-0 bond lends credence to the proposal of a molecularly adsorbed O2 precursor state in iron oxidation. IntroductionThe interaction of oxygen with Fe atoms is of interest because of its bearing on such diverse processes as corrosion of structural metals and oxygen transport in biological systems.

No abstract

The adsorption of triglyceride by silicic acid from hexane miscellas was observed with diffuse‐reflectance Fouriertransform infrared spectroscopy. Triglyceride was adsorbed by hydrogen bonding to silanol groups through the ester carbonyl group. Addition of isopropanol (IPA) to the triglyceride‐hexane solution prior to adsorption resulted in unchanged triglyceride adsorption on silicic acid despite IPA's ability to adsorb on silicic acid and hydrogen‐bond with triglyceride. Washing the triglyceride, adsorbed on silicic acid, with hexane containing IPA resulted in partial desorption of the triglyceride and a small amount of IPA being adsorbed. Triglyceride desorption into fresh hexane‐IPA is due to the establishment of a new equilibrium of lipid and IPA between hexane and silicic acid. The relative strengths of all the possible pairwise interactions among triglyceride, IPA and silicic acid are revealed by the relative amounts of adsorption under various conditions.