[Wien] Band Labeling

[Dr. Sharat Chandra]

Dear Users

How do we label the bands in the band structure that we have calculated
for some compound? I have read up some materials on the subject, but till
now I have been able to get some rumor level ideas only. Can some body
please point out some good references for the topic, and lay out some
algorithm as to how to go about it practically? The band structures that I
am talking about are for tetragonal materials the data for which is not
available do readily in literature.

Questions are:

1. How do we get the block matrix and irreducible representations of the 
   Hamiltonian matrix?
2. How do we assign to the bands the labels based on the point group 
   operations for some symmetry point?

I will appreciate any comments.

Regards
Sharat Chandra