The potential format 0 is used for analytical potentials exclusively. All header tokens are supported except for the #G line.

Each analytic potential function has to be specified as follows:

type identifier
cutoff value
param_1 value min max
param_2 value min max
...

The type keyword has to be followed by the unique identifier for your potential. You can also enable the smooth cutoff option by adding a _sc at the end. After the cutoff keyword the cutoff radius for this potential has to be given. This is independent for every potential and can thus be different for different potentials. The next line starting with # is a comment which is written by potfit. It indicates the minimum neighbor distance for this interaction. Following these lines, the values for the analytic parameters have to be specified. Each line starts with an identifier for that parameter followed by the starting value, the minimum and maximum value for that parameter. The order of these parameters is fixed, for the implemented analytic functions the order can be found here.

A sample format 0 potential file for a binary system with an EAM potential is available here.