Dear LAMMPS users:
I am simulating a triblock copolymer using COMPASS parameters, solvated in
water using TIP3P and SHAKE. I have been running nvt simulations that have run
for about 10,000 timesteps and then ended in errors with "WARNING: Dihedral
problem" and "Shake determinant = 0.0." I have checked all of my polymer's
I changed the command for the neigh_modify list to "every 1," to see if it's
a neighbor list problem, but I still got dihedral errors after 12,000 timesteps.
Decreasing the timestep from 0.5 to 0.05 (real units) and running for an
equivalent period of time did not solve the error problem.
I also increased the max iter. number for SHAKE from 10 to 20, but I still
got the same errors.
Additionally, simulating the polymer for about 100,000 timesteps (0.5 fs)
without water did not give any dihedral problems.
Any help in this matter would be appreciated. If needed, I can attach my
input and data files.
Chemical Engineering Dept.
Iowa State University