huckelEnergyDiagram[eigenvalues_] := Module[{workelist, lines},
workelist = Tally[Sort[Rescale[eigenvalues]]];
lines =
Table[{{0, workelist[[i, 1]]}, {1, workelist[[i, 1]]}}, {i, 1,
Length[workelist]}];
Table[For[workelist, workelist[[i, 2]] > 1,
workelist[[i, 2]] = workelist[[i, 2]] - 1,
lines = Append[
lines, {{0 + 1.5 (workelist[[i, 2]] - 1),
workelist[[i, 1]]}, {1 + 1.5 (workelist[[i, 2]] - 1),
workelist[[i, 1]]}}]], {i, 1, Length[workelist]}];
Print["Energy levels missing:",
Length[lines] - Length[eigenvalues]]