# How to generate a pseudopotential for a cation/anion?

Many DFT codes use pseudopotentials to represent the electron-ion interaction (as do most plane-wave codes and in contrast to so-called "all-electron" programs).

There are several resources on the web to generate pseudopotentials in different formats and for different DFT codes. One of them is the program ATOM. Bellow is an example ot the ATOM input file for carbon.

       pg                  -- file generated from C ps file
tm2
C   ca
0.000     0.000     0.000     0.000     0.000     0.000
1    4
2    0     2.000     0.000    #2s
2    1     2.000     0.000    #2p
3    2     0.000     0.000    #3d
4    3     0.000     0.000    #4f
1.56000   1.56000   1.56000   1.56000   0.00000   0.00000

#23456789012345678901234567890123456789012345678901234567890      Ruler


My question is: how to generate a pseudopotential for a cation/anion?

• I don't really know how to do it, but wouldn't one expect the net charge to be irrelevant to represent the inner core of an atom? – Michael F. Herbst May 18 '20 at 12:56