ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The products derived from the UV photolysis of Fe(CO)5 physisorbed onto porous Vycor glass have been examined by x-ray microprobe analysis, Mossbauer spectroscopy, and extended x-ray absorption fine structure spectroscopy (EXAFS). Although the photolysis and subsequent heatings are carried out in air, spectroscopic data reveal two surprisingly different forms of iron. Isomer shift, pre-edge, and EXAFS data indicate that one product is similar to α-Fe2O3 and consists of an Fe3+ ion octahedrally surrounded by six oxygen atoms at a distance of 1.8 A(ring). Isomer shift, EXAFS, and pre-edge feature analysis show that the second compound, which comprises ∼50% of the reaction product, is mainly elemental iron, in which a central Fe atom is surrounded by approximately eight other Fe atoms at a distance of 2 A(ring). X-ray microprobe analysis shows that aggregation occurs during photolysis due to the diffusion of Fe(CO)5 from the interior into exterior photodepleted volumes of glass. Heating has little effect on product ratio or distribution, but consolidating the glass at 1200 °C leads to further aggregation and formation of magnetically ordered particles that exhibit magnetic hyperfine fields of 370 and 425 kG.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.354468
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