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 the analytic function. To enable the smooth cutoff option _sc can be added at the end of the identifer (this also adds another parameter to the end potential function!).

Examples:

# plain Lennard-Jones potential
type lj
epsilon 1 0 2
sigma 1 0 2

# Lennard-Jones with smooth cutoff option enabled
type morse_sc
epsilon 1 0 2
sigma 1 0 2
h 1 0 2

The cutoff keyword is required to specify the cutoff radius, which may be different for each potential function. The minimal distance for each potential function is calculated by potfit from the configuration file and will be present in the output potential as a comment after the cutoff line.

cutoff 7.0
# rmin 2.2

This indicates the minimum neighbor distance for this interaction is 2.2 units of distance.

After the keywords 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.

format_0_example.txt

#F 0 1
#C Al
## Al-Al
#E
 
type lj_sc
cutoff 7.000000
# rmin 2.159655
epsilon 2100.0633799282 0.500000 10000.000000
sigma 10.3066290006 1.000000 20.000000
h 1 0.5 2

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