Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I know that the rotation energy of a diatomic homonuclear molecule is $E_{Rot}=\frac{\hbar J(J+1)}{R^2 M}$. Does the axis of rotation depend on $J$? With respect to which axis does the molecule for $J=1$ and why is that so?

share|cite|improve this question
up vote 1 down vote accepted

The axis of rotation does not depend on $J$, at least in this case. Furthermore, a diatomic homonuclear molecule only has one distinguished axis of rotation: With the atoms at $(-1,0,0)$ and $(1,0,0)$, it is impossible to differentiate between the $y$ and $z$ axis in terms of rotational energy (the $x$ axis does not contribute/it is impossible to decide whether the molecule roates about the $x$ axis).

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

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