Hi steve:

Recently,I have read some papers about free energy calculations of solid by thermodynamics integral method developed by Frenkel.This method can compute the solid and liquid absolute free energy by introducing a coupling parameter lambda and this method need a reference configuration of system,such as Einstein crystal.So ,If I want need to calculate absolute free energy of certain solid by LAMMPS ,I need potential of Einstein crystal and a hybrid potential function that contains lambda and can control the particle motions.However ,I didnâ€™t find the Einstein potential and corresponding functions in LAMMPS .

So,dear steve ,I want to kown whether LAMMPS provide the Einstein potential and some funtions to construct the hybird potential that contain parameter lambda,whether I have to write code if I want to realize that?