Some tools to compute energy levels for atomic structures drawn with ASCII art
This is a complete working project. I'm probably not going to do much future development on it.
For example, if you run butterfly.py it stores a (high resolution version of) this image in hex.1000.jpg:
That was created by drawing this ASCII art
A-B C-D E-B G-H I-J K-L M-N O-P Q-R S-T U-V W-X Y-Z a-b
/ \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \
o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o
\ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ /
A B C D E B G H I J K L M N O P Q R S T U V W X Y Z a b
That is used to represent an infinite hexagonal lattice. The letters A-Z are used to indicate identified points so the above represents the infinite (in vertical extent) lattice
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o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o a-b
/ \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \
o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o
\ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ /
o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o a-b
/ \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \
o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o
\ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ /
o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o o-o a-b
/ \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \
See Hofstadter's butterfly for my original motivation for this project.
It's fairly flexible. For example it had no trouble reproducing the energy levels for the graphene spirals in this paper.