usage: python pynergy.py [-h] -i INPUT -v VALENCE -e ENERGY [-d DELTA]
This script calculates transition energies between energy bands using eigen-
energy files generated by ABINIT during a band structure calculation. This
script allows you to input a desired energy value and finds all the upward
transitions that can produce that value within a specified tolerance. You can see the full script instructions by running with the -h option:
$ python pynergy.py -h
If the input file is an unformatted EIG file produced by ABINIT, you can use the adjoining 'eigenconvert.py' program that will automatically format it to a plottable file:
$ python eigenconvert.py inputfile outputfile
You can then use that file to calculate the transitions. You can generate a sample output with
$ python pynergy.py -i eigen_formatted -v 3 -e 6.81
This creates two files, transitions.txt and gnuplotarrows. The first is a text file that writes out the information about each transition, and the second is contains the lines necessary to produce arrows in Gnuplot. Simply load the file from within Gnuplot and rep to get your arrows.
A good gnuplot arrow style can be
set style arrow 3 head linetype 1 linecolor rgb "#000" linewidth 1.5 size screen 0.01,7,90