potfit wiki

open source force-matching

User Tools

Site Tools


examples:potentials:pair:5

This is an old revision of the document!


Examples : Pair Potentials

This is a simple pair potential that can be used in potfit. The analytic function used is a Lennard-Jones.

It makes use of the fixing parameters feature.

Example_Pair_5
#F 0 3
#T PAIR
#I 0 0 0
#E

type lj
cutoff 6.0
epsilon 0.10    0.00    0.00
sigma   2.50    1.00    4.00

type lj
cutoff 6.0
epsilon 0.10    0.10    0.10
sigma   2.50    1.00    4.00

type lj
cutoff 6.0
epsilon 0.10    1.00    1.00
sigma   2.50    1.00    4.00

The optimization of single parameters can be disabled with this feature. It will be removed from the optimization table and remain at the initial value. For all three lj-potentials in the above example the epsilon parameter will not be optimized, it will always have the fixed value of 0.1. To fix a parameter, the lower and upper bound have to be the same.

makeapot

The example potential can be generated with the following makeapot command:

The parameters have to be fixed manually in the potential file!

makeapot -n 2 -i pair -f 3*lj
examples/potentials/pair/5.1376575323.txt.gz ยท Last modified: 2013/08/15 16:02 by daniel