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 (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

 

[denian]

I can say that there is indeed a minimum energy required to flip the intrinsic spin of an electron from up to down or vice versa. This energy is known as the Zeeman energy and it is directly related to the applied magnetic field. The higher the magnetic field, the higher the Zeeman energy required to flip the spin of the electron. This phenomenon is known as the Zeeman effect and it has been well studied and documented in the field of quantum mechanics. Therefore, the minimum energy for a spin flip is not a fixed value, but rather dependent on the strength of the applied magnetic field.