**Number of accessible atoms for electronic state**

There is a possibility to calculate number of accessible atoms for each electronic state. See James P. Lewis et.al, Phys.Chem.B 2003,2581-2587 [[http://pubs.acs.org/doi/abs/10.1021/jp026772u]].

**input files**

To write out number of accessible atoms for electronic states keyword iwrtpop must be set equal to 1 in ''fireball.in'' inside &OUTPUT. ''fireball.in'' file should look like:

  
&OPTION
  basisfile = answer.bas
  nstepf = 1
  icluster = 1
  ifixcharge = 1
  dt = 1
  &END
  &OUTPUT
  iwrtpop = 1
  &END

The range of states for wich number of accessible atoms is calculated can be limited. To limit range we use ''pop.optional'', which has 2 rows: lower energy range and upper energy range.

  5
  -5

**output file**

Output is printed inside populations.dat file. Example of ''populations.dat'' file is shown below.

  # Charge localizations (per level): 
        11     -9.64513103     12.49797560
        12     -9.18338369     12.92085253
        13     -8.95862996      7.36921943
        14     -8.56804881     15.36345916
        15     -8.27237127     13.79320978
        16     -7.87184931     14.65046663
        17     -7.71855779     11.35161170
        18     -7.63186715     12.51387664
        19     -6.99028529      6.93401336
        20      4.53404975     10.64918441
        21      4.68221513     14.74267356
        22      5.00413004      9.77584252
        23      5.04746077      8.79292322
        24      5.17910737     13.05464686
        25      5.48947376     12.36298514
        26      5.62613229     12.61480031
        27      5.80260151     11.84900784
        28      5.97545566     10.95428560
        29      6.32086465      9.37627511
        30      6.73658853      9.09838490
        31      6.82112427      9.44451327
        32      6.99729984      7.38632597
        33      7.69235735     13.23298417
        34      7.90456769     14.01755604
        35      8.06294828     10.46461582
        36      8.28307352     14.50423183
        37      8.53459509     11.33495703
        38      8.72411300      8.14358126

Where first  column is number of molecular orbital, second is energy and third is number of accessible atoms (localization).