What causes paramagnetism and diamagnetism

[ColinD]

Paramagnetism: How does having an unpaired electron attract it into a magnetic field. Why not repel? Is there any reason or we just know from experiment?

Diamagnetism: If the electron spins and therefore magnetic fields cancel, what is causing it to repel from a magnetic field? If it is neutral, how is it repelled exactly?

Thanks for any help.

 

[Lok]

Hello Colin,

As this is a complicated subject to explain I would start with this from min 4:00 to 11:00 Lecture where a bit of molecular diamagnetism is graphically shown.