Regarding Lattice parameter

Dear Lammps users,
I am calculating Equilibrium lattice parameter at 300K temperature through NPT dynamics. After averaging it over a no. of timesteps after initial large fluctuation for a few timesteps, it comes out to be 3.6327 A. However in literature, it is usually given as 3.6149 A. So is it the right way to calculate or something is going wrong?

pair_style eam
pair_coeff * * Cu_u3.eam
velocity all create 300 2223333 temp new
fix 1 all npt temp 300 300 0.1 iso 0.0 0.0 1

run 10000


  1. Is 3.6327 an averaged value or just the final instantaneous value?
  2. What is the timestep size? 10000 steps might be too short.
  3. 3.6149 is likely from experiments - what is the value from the original paper that published Cu_u3.eam? That is the value you should compare to.