Hi all,
I am performing a rigid body simulation of identical dumbbells using LAMMPS version 29 Aug 2024. Each dumbbell consists of two point masses. I am calculating the moment of inertia of the dumbbells using two methods: compute rigid/local and compute chunk/atom molecule.
The moment of inertia of a dumbbell, with respect to its center of mass, is 0.5 if the mass is one and the two masses are separated by a unit distance. However, for some dumbbell molecules (e.g., molecular IDs 437, 1372 and 348 in the output file rigid_inertia.dump), the moment of inertia is doubled. Since all the dumbbells are identical, then why the moment of inertia is twice the expected value for some of them.
Could you please help me to resolve this issue? The input files are also attached.
Dumbbell.in (1.8 KB)
mymol.txt (166 Bytes)
rigid_inertia.dump (347.3 KB)