Hydrothermal spring systems may well have been present on early Mars and could have served as a habitat for primitive life. The integrated instrument suite of the Athena Rover has, as a component on the robotic arm, a Mossbauer spectrometer. In the context of future Mars exploration we present results of Mossbauer analysis of a suite of samples from an iron-rich thermal spring in the Chocolate ...

the reaction kinetics of the isomerization 3,4-dichlorobutene-1 to 1,4-dichlorobutene-2 was investigated by using gas-liquid chromatography method in the presence of fe2o3/mgo as solid catalyst in the temperature range 25-55°c. fe2o3/mgo has been prepared by the support saturation method, tested in the isomerization of 3, 4-dichlorobutene-1 into 1, 4-dichlorobutene-2. this catalyst shows a high...

The well-known dependence on preparation conditions of the microstructural polymorphism in nc networks is often also reflected in their magnetic properties. This is particularly evident for non-metallic nc materials where superexchange coupling dominates. The latter is very sensitive to slight variations in bond lengths and angles. For example. this counterplay of local structural and magnetic ...

With an emphasis on assessment of reproducibility and precision of results, the technique of Mossbauer spectroscopy is applied to three groups of materials with increasing structural complexity: simple mineral standards, multivalent and multisite ferruginous micas, and multisite silicate glasses. In order to study the underlying accuracy of Mossbauer measurements of minerals, two mineral standa...

VIII VI IV Aenigmatite, Na4 (Fe2 +,Ti,Fe 3 +) 1 2 (SiFe 3 +) 12 0 40 , is a common constituent of sodium-rich alkaline igneous rocks and is classified as an open-branched single-chain silicate, whose structure is closely related to that of sapphirine. The first Mossbauer spectra of three valid aenigmatite specimens were recorded and the detailed crystal chemistry were obtained. In the Mossbauer...

~ong the easy axis a at 4.2 K induces phase transi­ tionsatHI =39 kOe andH2 =46 kOe [1-3]. In this ~t1er we report the use of Mossbauer spectroscopy in external magnetic fields to study the magnetic struc­ (ure of each of the three phases. Previous Mossbauer work in FeCI2 · 2HZ0 includes apower study by Chandra and Hoy [4] and a single z crystal study by Johnson [5]. They found a magnetic o hyp...