Mossbauer texture effects

From these results, it is concluded that, in a fully reduced catalyst, FeAl204 is not present furthermore, the aluminum inside the iron particle is present as a phase that does not contain iron (e.g., A1203), and this phase must be clustered as inclusions 3 nm in size. These inclusions may well account for the strain observed by Hosemann et al. From the Mossbauer effect investigation then, the process schematically shown in Fig. 17 was suggested for the reduction of a singly promoted iron synthetic ammonia catalyst. Finally, these inclusions and their associated strain fields provide another mechanism for textural promoting (131). 

The effect of anisotropy of atomic vibrations in solids not only causes the Mossbauer effect probability f to be anisotropic in single crystals, but may also lead to anisotropy in f for nontextured polycrystalline samples consisting of randomly orientated crystallites. The relative line intensities of the Mossbauer spectrum (Figures 3-6) will be different for negative and positive velocities. Similar deviations may be caused by texture, that is by a preferred orientation of crystals in a polycrystalline sample. 

---