Paramagnetic field

The diamagnetic field is associated with the electronic ground state wave-function in the absence of an external field, is generally aligned in a direction nearly antiparallel (opposite) to that of the external field, and tends to cause an upfield shift of the nuclear resonance. The paramagnetic field is associated with the perturbed electronic functions, is generally in a direction nearly parallel with the external field, and tends to cause a downfield shift. 

The little atomic magnets are of course quantum mechanical, but Weiss s original theory of paramagnetism and ferromagnetism (1907) [7] predated even the Boln atom. He assumed that in addition to the external magnetic field Bq, there was an additional internal molecular field B. proportional to the overall magnetization M of the sample. 

The two primary causes of shielding by electrons are diamagnetism and temperature-independent paramagnetism (TIP). Diamagnetism arises from the slight unpairing of electron orbits under the influence of the magnetic field. This always occurs so as to oppose the field and was first analysed by Lamb [7]. A simplified version of his fomuila. 

ESE-detected EPR spectroscopy has been used advantageously for the separation of spectra arising from different paramagnetic species according to their different echo decay times. Furthemiore, field-swept ESE... 

Rhenium metal exhibits a very low paramagnetism which is field-iadependent and almost temperature-iadependent. In the range 79—471 K, magnetic susceptibiUty data for two independent samples were shown to correspond, when Tis ia Kelvin, to the following equations (5) ... 

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