Iron-oxygen interactions in an argon matrix

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.

Reactions of Laser-Ablated Iron Atoms with N2O, NO, and O2 in Condensing Nitrogen. Infrared Spectra and Density Functional Calculations of Ternary Iron Nitride Oxide Molecules

“…The sharp 1664.0, 1662.0 cm -1 doublet, which increased markedly on final annealing shows almost the same isotopic ratios as the FeNO bands, and intermediate components at 1646.6, 1642.5 cm -1 using 16,18 O 2 ; these observations suggest the Fe(NO) 2 complex. An analogous band was observed at 1666.9 cm -1 in solid argon.…”

“…[1][2][3][4][5][6][7] However, the reaction of iron with nitrogen is less favorable as iron nitrides and dinitrogen complexes are not as stable relative to the highly stable N 2 molecule. 8 Nevertheless, iron nitrides have been prepared by the reaction of laser-ablated iron atoms with nitrogen atoms and molecules.…”

Density functional study on cage and noncage (Fe2O3)n clusters

“…Many previous experimental and theoretical works have been done on this issue. In experiments, iron oxide clusters were studied by means of infrared ͑IR͒ spectroscopy, [6][7][8] laser induced fluorescence spectroscopy, 9,10 photoelectron spectroscopy, [11][12][13][14] Mössbauer spectroscopy, 7 and various mass spectrometry based methods, [15][16][17][18][19][20][21] including collisional activation, charge reversal, neutralization reionization, IR multiphoton dissociation, multiphoton, single photon ionizations, etc. Reactions of iron oxide clusters with small molecules such as H 2 , N 2 , CO, CO 2 , and hydrocarbons were studied to understand the adsorption, reaction, and catalytic properties.…”

Formation and Characterization of Two FeO3 Isomers in Solid Argon

“…[1][2][3][4][5][6][7][8][9][10][11] The FeO 2 molecules in the form of oxo, peroxo, and superoxo were proposed to be reaction products between the iron atom and molecular oxygen in solid matrixes. [12][13][14][15][16] However, gas phase investigations indicate that ground-state iron atoms are unreactive toward dioxygen at room temperature. 17,18 Anion photoelectron spectroscopic investigation also indicates that only the inserted OFeO structure was observed.…”