[lammps-users] Problems with NEB method


I am trying to do an analysis on punctual defects migration energy using the nudged elastic band method. I built a simple model bcc with adding an intersitial atom.

I did a previous simulation dumping a data file to use it as initial file.

Then I created a final file in which I insterted just the interstitial atom ID and its final coordinates, supposing it jumps on an adjacent interstitial location.

I use the following two lines for running the neb simulation and 6 replica

fix 1 nebatoms neb 1.0

neb 0.0 0.01 100 100 10 final final.vac

First of all I would ask if there is a quick way for running the analysis for many defects and many migration paths for each defect (instead of generating a defect and writing its .final file by hand each time).

Secondly, my master log.lammps file shows just the data about one of the replica and its timesteps. I guess it is the highest energy replica, the one on the saddle point, but I would like to see data of all the 6 replica. For instance for plotting the pe against the reaction coordinate.

Thank you.



  1. LAMMPS has no automated mechanism for generating all possible NEB end points
    for multiple defects and paths. That is probably more of a job for a pre-processing script
    which generates a series of LAMMPS NEB scripts. If you write such a tool,
    please contribute it to the LAMMPS distribution!

  2. For any multi-replica simulation, including NEB, LAMMPS should generate a collection
    of log and screen files which correspond to each replica. The neb doc page explains this.