How do rotational and vibrational energies in molecules depend on masses?

[meteor84]

Hi!

I'm wondering what the effects of a variable mass of elementary particles on the rotational and vibrational energy-transitions would be like? Would they increase, decrease or stay the same?

Thank you for your help!

Regards

 

[DrDu]

See:

http://www.ulb.ac.be/cpm/people/scientists/bsutclif/bornop.pdf

 

[cgk]

On a related note: What to do with the electron masses is not actually so clear. In principle they should be handled by the BO expansion and vibrational spectra should be calculated using bare masses. But in approximate treatments they are often included, because this seems to work better (note: this has an effect of <2 cm^{-1} in most cases).

See http://dx.doi.org/10.1080/00268970701604671 for a deeper discussion of this topic.

 

[DrDu]

Yes, an exact formulation of the BO perturbation expansion is highly non-trivial. I visited once a summer school on that topic where Kutzelnigg was one of the speakers.
Here a review by Hagedorn:
http://www-fourier.ujf-grenoble.fr/~joye/simon2006.pdf