Basis of the magneto-optical method

The experimental arrangement is sketched in fig. 4.8. Plane polarised radiation is incident on an absorption cell placed between two crossed po-larisers in a magnetic field. The direction of the magnetic field is parallel to the direction of propagation. It is helpful to consider the three classical geometries associated with a+, 7r and a polarisations. These are 

Magneto-optical activity results from the asymmetry in the indices of refraction for the left (—) and right (+) hand polarised circular components of a light wave induced in a medium by a longitudinal B field. It subdivides as shown in table 4.2. 

The plane of polarisation of the wave is rotated as a function of detuning from the line centres, because the two circular components suffer relative retardation as they traverse a length i of the absorbing column, owing to the differences of refractive index for r+ and a light. This effect is 

Magnetic circular dichroism (MCD) Magnetic circular birefringence (MCB) 

Due to the difference between the absorption coefficients a+(i/) and a (v), we have an ellipticity angle for initially plane-polarised radiation Due to the difference between the refractive indices +(v) and (v), we have a rotation angle of plane-polarised radiation  

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