Can atoms have Vibrational and Rotational energy levels?

[CGandC]

Homework Statement

I know that molecules can have vibrational and rotational energies, but I'm unsure as to whether atoms can also have vibrational and rotational energies , if atoms don't have vibrational and rotational energy levels, then why? or if they do then why?

Relevant Equations

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I found one answer somewhere else in the internet, It specified there that atoms cannot have rotational and vibrational energies since they don't have a point on them that will allow the atom to be rotated or vibrated. However , that answer did not suffice so I ask the same question here.

 

[.Scott]

The reason that an atom cannot "spin" in the common sense is that it is so tiny and light weight that Heisenberg Uncertainty immediately dulls any specific location for its components. For example, its electrons do not really "orbit" its nucleus. Instead they form clouds where an electron is most likely to be found in the densest parts of those clouds.

But there is more to the story than this. For example, I would expect that an ethane molecule (~30g/mol) could hold some angular momentum, but an atom of gold (~197g/mol) could not. In the case of the atom, most of the weight is concentrated in a nucleus that is too small to spin in the conventional sense and is surrounded by an electron cloud whose behavior is determined by QM rules such as the Pauli principle.

 

[Borek]

To add to what .Scott wrote: try to estimate moment of inertia of hydrogen molecule and hydrogen atom (remember: most of the mass is located in the nucleus, you can assume proton radius for the nucleus). Compare these numbers.