Questions on the classical interpretation of (normal) Zeeman effect

[ValeForce46]

I'll put pictures from the book as I think they are relevant to understand the problem:

I have trouble understanding the case where the observer watches the source in a direction perpendicular to the magnetic field. The electron will rotate around B axis, so the observer will only see a linear oscillation of the electron hence linearly polarized light.
But how can the Lorentz force explain the splitting of spectral lines? The book suggest to view the linear oscillation as a combination of two counter-rotating motions like this:

But if this is the case, the Lorentz force would act in a plane perpendicular to the image so it won't explain the change of the frequency of the circular motion of the electron (and so the Zeeman splitting, classically).
Instead the situation is clear when we observe along the direction of B, as in that case Lorentz force would act radially.

 

[PeterDonis]

@ValeForce46 this is the quantum physics forum. Why are you using classical physics to analyze this problem?

 

[ValeForce46]

@ValeForce46 this is the quantum physics forum. Why are you using classical physics to analyze this problem?

Sorry, I shouldn't have posted here. It was my first impulse, because this is just the introduction to the Zeeman effect and later the book use quantum physics to explain it.

 

[PeterDonis]

Should this thread be deleted?

 

[ValeForce46]

If it can't be moved, yes. I'll re-post on classical physics. Sorry.

 

[PeterDonis]

I can move it to classical physics, but the answer there is simple: the Zeeman effect isn't a classical effect so there is no classical explanation for it. Is it even worth moving the thread?

 

[ValeForce46]

Well, according to the book I am reading (from which I took the pictures I posted), "Introduction to the Structure of Matter: A Course in Modern Physics" by John J. Brehm and William J. Mullins, there is a classical interpretation, at least for the "normal" version (no spin is involved yet) of the effect where we see splitting in just 3 lines.

 

[PeterDonis]

according to the book I am reading (from which I took the pictures I posted), "Introduction to the Structure of Matter: A Course in Modern Physics" by John J. Brehm and William J. Mullins, there is a classical interpretation, at least for the "normal" version (no spin is involved yet) of the effect where we see splitting in just 3 lines.

I don't see how there can be a purely classical interpretation since classical physics can't even explain the existence of spectral lines in the first place--or the existence of atoms, for that matter. According to classical physics electrons around an atomic nucleus should emit a continuous spectrum of radiation as they spiral into the nucleus; there should be no spectral lines and atoms should not be stable.

The book might be using a classical approximation of QM for this particular phenomenon, which would be based on an underlying quantum model.

 

[vanhees71]

I guess it's using the old quantum theory a la Bohr and Sommerfeld. I'd not recommend any book, which dwells on this old-fashioned theory, which provides wrong pictures even on the qualitative level. Also one should stress that particularly the Zeeman effect was among the many hints at the failure of these models and was understood only with the modern QT and the introduction of spin, i.e., the Pauli Equation.

 

[ValeForce46]

Well, thank you anyway for the replies. I suppose, if my questions have no answers, you might as well delete this thread.

 

[PeterDonis]

I suppose, if my questions have no answers, you might as well delete this thread.

On further consideration, the information that there is no classical interpretation of the Zeeman effect might be useful for other readers, so the thread will remain visible.