Can a neutral atom be affected by magnetic field?

[s0ft]

If we have a moving, neutral atom, say hydrogen, will it react to a magnetic field?
If yes, why?
If you ask why not, I argue that the atom as a whole is a chargeless entity.

 

[mikeph]

Yes. A group of charged particles with zero net charge can still have non-zero magnetic moments. The particles may have orbital angular momentum (such as the electron in hydrogen) or intrinsic spin, and these can all interact with magnetic fields.

 

[s0ft]

So, if the atom had a zero net magnetic moment, then it wouldn't be affected right? And is such an atom possible?

 

[VantagePoint72]

So, if the atom had a zero net magnetic moment, then it wouldn't be affected right?

Right.

And is such an atom possible?

Yes. un-ionized, unexcited Helium-4 has no magnetic moment: its electrons are both in the s-orbital (so no angular momentum) and the two electrons, two protons, and two neutrons are all respectively anti-parallel, so there is no total magnetic moment due to spin.

 

[DrDu]

http://en.wikipedia.org/wiki/Stern–Gerlach_experiment

Stern and Gerlach used neutral Silver atoms in their experiment.

 

[DrDu]

Right.



Yes. un-ionized, unexcited Helium-4 has no magnetic moment: its electrons are both in the s-orbital (so no angular momentum) and the two electrons, two protons, and two neutrons are all respectively anti-parallel, so there is no total magnetic moment due to spin.

Even Helium will show diamagnetic behaviour in a magnetic field so it will be influenced.

 

[Integral]

Think Iron.

 

[sophiecentaur]

If we have a moving, neutral atom, say hydrogen, will it react to a magnetic field?
If yes, why?
If you ask why not, I argue that the atom as a whole is a chargeless entity.

An external magnetic field will 'affect' the absorption lines of many neutral atoms. See Zeeman Effect.

 

[s0ft]

What about Lorentz force, on a moving neutral atom?