I read through the thread:
which discussed on how the scaling factors for fix rigid/nvt, fix rigid/nve were corrected. The discussion also shows that there should be no moment-of-inertia problems for linear molecules.
But when I tried my system, both ‘fix rigid’ and ‘fix rigid/nvt’ generated the same error “Fix rigid: Bad principal moments”. I don’t know why this happened. The version of LAMMPS I used is the latest 9Sep2010.
Attached is my input files.
BTW, it occurred to me just now. Is it OK for the input coordinates file to have the rigid bodies be divided by the periodic boundary?
CO2.zip (32.1 KB)