I am learning about how to apply group theory analysis of MO diagrams and vibrational in the solid state context (not isolated molecules).

I think the strategy for calculating representations and getting the the orbitals/vibrations with distinct symmetry is quite clear for normal point groups. Essentially you forget about the solid state part of the problem for the most part and just look at the unit cell as a large "molecule".

To incorporate crystal momentum, the unit cell becomes large enough to contain one wavelength of the corresponding wave. This is more complicated, but it seems like you just do a symmetry analysis of a larger unit cell with (typically) lower symmetry.

Now I am trying to understand how this process extends to nonsymmorphic space groups (not point groups). Here I have trouble finding character tables online, and the screw axes/glide symmetries throw off my intuition.

So my question is: how do we apply group theory for bonding and vibrations in the context of nonsymmorphic space groups? I guess it should be the exact same as usual, but it just doesn't seem intuitive how bonding should care about screw axes or glide symmetries that connect far away atoms.


Your Answer

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

Browse other questions tagged or ask your own question.