[Pw_forum] band vs plotband output.

[Davide Tiana]

Dear all,
I found some cases where after reorganise the bands output with plot  
bands, the homo - lumo are swapped. Why does his happen? More  
important to calculate the Band Gap what values should I used?

here an example: electron = 94, homo band numb 47.
band.out
           k = 0.0000 0.0000 0.0000     band energies (ev):

    -55.9850 -55.9850 -27.9953 -27.9953 -27.9793 -27.9793 -27.9357 -27.9357
    -20.6223 -20.5647 -19.6426 -17.8930 -17.1262 -15.8489 -15.6076 -14.4238
    -13.4669 -12.7303 -11.1590 -10.9066 -10.8380 -10.8160 -10.7731  -9.7812
     -9.6601  -8.6932  -7.8692  -7.7732  -7.7280  -7.1303  -6.6701  -6.6130
     -6.1019  -6.0213  -5.5373  -5.2958  -5.0030  -4.4158  -4.2662  -4.0390
     -3.8182  -3.7469  -3.6889  -3.6568  -2.7622  -2.1193  -1.5121  -1.4329
     -1.0247  -0.6744   0.1096   0.2954   0.4064   0.7536   0.8100   1.0277
...
           k = 0.0000 0.0000 0.8327     band energies (ev):

    -55.9850 -55.9850 -27.9953 -27.9953 -27.9793 -27.9793 -27.9357 -27.9357
    -20.6203 -20.5647 -19.6429 -17.9201 -17.1113 -15.9214 -15.4652 -14.2886
    -13.7199 -12.6999 -11.5050 -10.9082 -10.8380 -10.8359 -10.6059  -9.7363
     -9.1694  -8.6237  -8.2259  -7.6547  -7.4356  -7.3467  -6.8330  -6.5799
     -6.3278  -5.8338  -5.4976  -5.2352  -4.9676  -4.7183  -4.5833  -4.1295
     -4.0561  -3.6146  -3.2923  -2.9937  -2.9251  -2.6585  -1.5326  -1.4329
     -0.9754  -0.6156   0.3641   0.4861   0.5199   0.5499   0.5910   1.0285

bands.dat
0.000000  0.000000  0.000000
  -55.985 -55.985 -27.995 -27.995 -27.979 -27.979 -27.936 -27.936  
-20.622 -20.565
  -19.643 -17.893 -17.126 -15.849 -15.608 -14.424 -13.467 -12.730  
-11.159 -10.907
  -10.838 -10.816 -10.773  -9.781  -9.660  -8.693  -7.869  -7.773   
-7.728  -7.130
   -6.670  -6.613  -6.102  -6.021  -5.537  -5.296  -5.003  -4.416   
-4.266  -4.039
   -3.818  -3.747  -3.689  -3.657  -2.762  -2.119  -1.512  -1.433   
-1.025  -0.674
    0.110   0.295   0.406   0.754   0.810   1.028
..            0.000000  0.000000  0.832734
  -55.985 -55.985 -27.995 -27.995 -27.979 -27.979 -27.936 -27.936  
-20.620 -20.565
  -19.643 -17.920 -17.111 -15.921 -15.465 -14.289 -13.720 -12.700  
-11.505 -10.908
  -10.838 -10.836 -10.606  -9.736  -9.169  -8.624  -7.436  -8.226   
-7.655  -7.347
   -6.328  -6.833  -6.580  -5.834  -5.498  -5.235  -4.968  -4.718   
-4.583  -4.056
   -3.292  -4.129  -2.925  -3.615  -2.994  -2.658  -1.433  -1.533   
-0.975  -0.616
    0.550   0.364   0.520   0.486   0.591   1.028

band.out
HOMO -1.5121  LUMO -1.4329
HOMO -1.5326  LUMO -1.4329

bands.dat
HOMO -1.512  LUMO -1.433
HOMO -1.433  LUMO -1.533

Thank you for helping me