Mossbauer spectroscopy provides information about the oxidation state of Fe and its chemical environment with 57Co source. Parameters like isomer shift, quadrupolar splitting, magnetic hyperfine coupling constant and line width are obtained.

Sample Required

Sample can be in the form of powder or pellet (10 mm diameter) or a metal foil. Concentration of the Fe should be 25 mg/mm2. Velocity range for scan must be specified.
 

Description

In Mössbauer spectroscopy, a source emitting monochromatic gamma radiation moves at a constant velocity leading to a change in frequency of the gamma radiations by Doppler's shift and hence its energy. This is absorbed by the sample, reemitted and detected. Thus, the spectrum is basically one of velocity vs. intensity plot.

Canberra S-100 spectrometer contains a 57Co source, a sample stage and a proportional counter as a detector. The motion of the source is completely synchronous to the sweep of the multichannel analyzer (MCA). The counts obtained by the MCA are stored by a dedicated IBM PS/2 computer on a disk file. The counts and spectrum are presented on a HP laser jet printer. The velocity range of MDU-1200 drive unit is 0-1000 mm.sec at a resonance frequency of 23 Hz. MVC-450 Laser velocity with He-Ne laser of 0.5 mW (calibrator) is available. Source is 57Co with 6 mm active diameter and 12 mm open which emits Y-rays of 14.4 keV energy. MCA: 128 to 4098 channels; SINUS (constant velocity) and Triangle wave (constant acceleration) are present. Oxford MD306 cryostat with exchange gas is available for various temperature measurements in the region 77-300 K are available with liquid nitrogen as coolant.

 

Application

  • Analysis of compounds containing iron can be done. Most of its use is for research in chemistry, nuclear physics and solid state physics.
  • Iron containing biological samples like hemoglobin, phase transitions and solid-state reactions can be studied.
 
 
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