[lammps-users] ERROR: Shake clusters are connected


I am using SHAKE algorithm for Nitrobenzene in oder to account rigid structure of the molecule. But, this ERROR: Shake clusters are connected. I need your kind suggestions in order to solve this. My model details:

group nbz type 3 4 5 6 7 #atoms connected in NB and 3, 4 are ids carbons viz., CN, CA

neighbor 1.0 bin
neigh_modify delay 0 every 1 one 6000
minimize 1.0e-4 1.0e-6 1000 10000
fix 1 all shake 0.0001 20 0 t 3 4 a 4 b 3

Thanking you.

Srinivas Tulishetti

Are you following the restrictions on fix shake in LAMMPS
described on its doc page? If not, you can't use SHAKE
and will need to either use fix rigid or use an alternate
model of your molecules.