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Potential File Format 0
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 ...
type
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
cutoff
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.
parameter values
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.
Example
- 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 system with an EAM potential is available here.