Minimum energy for a spin flip?

[pivoxa15]

Is there a minimum energy to flip the intrinsic spin of an electron from up to down or vice versa? Or does it depend on the applied B field?

[marlon]

Is there a minimum energy to flip the intrinsic spin of an electron from up to down or vice versa? Or does it depend on the applied B field?

The external B field is necessary to induce a spin flip (spin down to spin up for example). The associated energy depends on this B field but the also on the spin magnetic moment (http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/nmr.html#c1) (or more specifically the z-component thereof). This quantity is expressed in terms of a constant called the Bohr magneton. Lots of imaging techniques (MRI) are based upon the principle of "inducing spin flips" (NMR).


marlon