1
$\begingroup$

I am a beginner at orbitals. It seemed interesting to me while studying p orbitals that the texts don't suggest that the orbitals are rigid relative to the nucleus.

But I thought mathematically these rotations would not be possible to know because the wave function of the orbitals only tell about the probability. Until this:(Simple rotation of an atomic orbital wavefunction)( I didn't understand it as I don't know the mathematics; I am trying)

So, is it possible for orbitals to rotate relative to the nucleus? If yes, what validates it; if no, what disallows it?

$\endgroup$
  • 1
    $\begingroup$ What do you mean by the oribitals "rotating"? By definition, the orbitals are stationary states, i.e. they do not change in time. $\endgroup$ – ACuriousMind Dec 9 '16 at 15:45
  • $\begingroup$ Maybe I missed that point. Then what does rotation mean in that question? What prohibits their 'movement'? $\endgroup$ – Partha Sarker Dec 9 '16 at 16:11
  • 1
    $\begingroup$ I presume you've been looking at some set of visualizations—the pictures that show p-orbitals as dumbbell shapes, say. There are at least two ways to interpret this question in it's current form: (a) do the dumbbells have to be lined up on the axes as they are usually shown (answer, no the choice of axes is arbitrary) and (b) if I know that an electron exists in p-orbital that is currently lined up with the x-axis and look again a little later could I find it in a dumbbell at an angle with the x-axis. The second question is not very well posed, but as @ACuriousMind's comment say "no". $\endgroup$ – dmckee --- ex-moderator kitten Dec 9 '16 at 17:09
0
$\begingroup$

Atomic p orbitals have angular momentum. The angular part of the wavefunction is described by the spherical harmonics $Y_{\ell,m}$ where $\ell=1$ and $m=-1,0,1$. When one multiplies this with the time-dependent part $e^{iEt/\hbar}$, the result is a rotating phase.

The $p_x$ and $p_y$ orbitals of chemical compounds are different linear combinations of $Y_{1,1}$ and $Y_{1,-1}$ without angular momentum along the z-axis.

Absorption of linearly polarized light may transfer an electron from an $s$ orbital to a $p_x$ orbital, but it will not remain oriented because of spin-orbit coupling.

$\endgroup$
0
$\begingroup$

The orientation of the p-orbitals which is related to the orbital angular momentum of the electrons is definite only upon measuring the angular momentum relative to an arbitrary axis (e.g. z-axis). Therefore, in general, it does not make sense to consider them to be rotating.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.