Interatomic Potential

Force acting between atoms are termed as interatomic potential. It is really important to specify this force in LAMMPS script. We do that using the commands pair_style and pair_coeff. There are different types of potentials available like LJ, EAM, EAM/Alloy etc. pair_style specifies the potential type and pair_coeff specifies potential values.

There are 2 methods to specify these potentials:

 One is mentioning all the force values in the input script directly. For example, the number of force values for LJ potential is too small that we can easily mention them in the script. This I have done in the last 2 Argon simulation blog. 

The second method is mentioning a file name on which force values are present so that LAMMPS will take the values from the file directly. This method is done where the number of force values is enormous. If we mention all the values the script becomes messy, also it is difficult to mention such a huge number of values. Follow my next blog. In that, I will show how to do this.

These interatomic potential/force values are experimentally calculated values. While you download LAMMPS it will also download a folder named "Potentials" on which you can find the potential files various elements. If you want potentials apart from these available potentials visit interatomic potential repository, from which you can download whatever the potentials you want. The potentials available in the website are experimentally calculated and are free to use.