[Wien] Band Identity in spaghetti

[Dr. Sharat Chandra]

Dear Wien experts

In the band structure plot generated by spaghetti, when any two bands are 
crossing at some point in the plot, the resulting degeneracy is lifted at 
the point of crossing and the two bands are separated. This results in a 
change of band identity. Suppose, at first band 1 is lower in energy, then 
after the point of crossing band 2 will be lower in energy. But after the 
point of band bending, band 2 will be higher in energy throughout the 
range. I want to know in what way the identity of the bands are given. Are 
they set after all the crossings are taken into account, or they are 
labelled starting from the band which is lowest in energy?

This becomes a problem, if the identies of the bands change after the 
crossing is taken into account. For example, I am interested in 
calculating the contribution to DOS from each band separately using the 
joint program. But this can be done correctly, only if the band identities 
do not change.

I tried to find an answer to this myself, but it is not clear from the 
documentation or the source code. Any comments will be quite helpful.

Regards
Sharat Chandra