Dear LAMMPS users:
I posted this question last week but I’m having problems with my e-mail and it seems it wasn’t correctly posted.
Here it goes again, sorry if I’m doubling the info and the messages.
I am simulating a channel of rutile (110) with a monolayer of SPC/E water molecules, using NVT and SHAKE fixes. The atoms in the solid phase are fixed via the wiggle fix with a 0,0 amplitude. I’m only SHAKEing the bond of the water molecules (or so I think).
The data file consists on the list of atoms, with full style. 180 atoms in total of which the first 156 correspond to the rutile channel and 157-180 to the water molecules. Similarly, molecule id=1 corresponds to the rutile channel and mol id>=2 to the water molecules adsorbed to the surface. I only list the bonds and angles corresponding to the water molecules.
I have been running nvt simulations that ended in the error “Shake determinant = 0.0.” I have checked all the parameters, I’ ve modified the tstep from 1 to 0,1 (real units) but I still get the same error.
Additionally, simulating the rutile channel only for about 0.5 ps without water did not give any problems.
For further details, I attach the data log file that ended with the error message “ERROR on proc 0: Shake determinant = 0.0”
The step number at which the message appears and the program crashes depends on the timestep I choose for the simulation. I have used values of 1-0.5-0.1 fs. I also tried modifing the drag value but it had no effect (values of 2, that I know is huge).
Using the same data file and only modifing the tstep and Tstart and Tstop in the nvt fix, my results were the following:
Tstart(K), Tstop(K), drag, tstep(fs), # steps
300, 300, 1, 0.2, 200- Error: Shake Det. 0.0
300, 300, 0.5, 0.2, 1100- Error: Shake Det. 0.0
300, 300, 0.1, 0.2, 1400- Error: Shake Det. 0.0
100, 100, 1, 0.2, 500- Error: Shake Det. 0.0
100, 100, 0.5, 0.2, 1500- Error: Shake Det. 0.0
100, 100, 0.1, 0.2, 35900- Error: Shake Det. 0.0
100, 100, 0.1, 2, 4800- Error: Shake Det. 0.0 (DIFFERENT DRAG VALUE)
I thank you in advance for your help, and I apologise again for the double-shooting.
data-slab-canal-14-relajado-monocapa (8.25 KB)
log.lammps (29.5 KB)