# IONIZATION POTENTIALS [eV] for the elements from NIST
 k j ion   chi_Ijk 
 1 1 H     13.5984340  
 2 1 He    24.5873876  
 2 2 He+   54.4177630  
 3 1 C     11.26030
 3 2 C+    24.38331
 4 1 N     14.53413 
 5 1 O     13.618054 
 6 1 Ne    21.564539 
 7 1 Na     5.139075 
 8 1 Mg     7.646231 
 8 2 Mg+   15.035255 
 9 1 Al     5.985755 
 9 2 Al+   18.82857
10 1 Si     8.151683
10 2 Si+   16.345845 
11 1 P     10.48669
11 2 P+    19.76947
12 1 S     10.3600
13 1 Cl    12.96763
14 1 Ar    15.759606
15 1 K      4.34066345
16 1 Ca     6.113158
16 2 Ca+   11.87172
17 1 Ti     6.8204
17 2 Ti+   13.5755
18 1 Cr     6.76651
18 2 Cr+   16.4857
19 1 Mn     7.434018
20 1 Fe     7.9024
20 2 Fe+   16.1877
21 1 Ni     7.6374
21 2 Ni+   18.168837