Testing ReaxFF Potential: Relaxation of Si Block

Two simulations of a Si block of dimensions 10x2x10 unit cells on a diamond lattice are shown. ReaxFF was used in the simulation on the left. A Tersoff potential was used on the right. The intent was to relax each system and compare the results. The systems were run for 200 times steps. The simulation using Tersoff appears stable near 0K (as well as 300K in another simulation not shown). However, the ReaxFF system is unstable: the temperature rises from 0K to ~31,000K in 200fs, with no forces applied. ReaxFF simulations were carried out using time steps of 0.025fs and 0.0025fs.

LAMMPS simulation inputs&outputs are the links below.

ReaxFF potential file:
http://njolee.net/LAMMPS/ffield.reax

ReaxFF input script:
http://njolee.net/LAMMPS/in.script.txt

ReaxFF output:
http://njolee.net/LAMMPS/log.lammps.ReaxFF.txt

Tersoff output:
http://njolee.net/LAMMPS/log.lammps.Tersoff.txt

Category:

Science & Technology