Measuring rotation frequency of a ring

Hi Lammps Users,

I have a structure like this (see photo). I have noticed that the middle ring rotates/flips during the simulation, which is very interesting.
Do you have an idea how I can measure the frequency of its rotation (representing rotation tendency/mobility of the ring)? How can Lammps help me in this respect? We need to measure this property and compare it with other structures, having other functional groups on the middle ring.

Thanks for your advice.


how about using compute omega/chunk?



Dear all,

I assigned the atoms of the middle ring to a group, and intend to investigate some of their properties using four related chunk commands. Hopefully they will show some indications of the rotation behavriors.
*If you have other ideas, please let us know.

group Mid_Ring type 12 13 14 15 19 20

compute Mid_Ring Mid_Ring chunk/atom molecule

compute myChunk_omega Mid_Ring omega/chunk Mid_Ring
fix Mid_Chunk_omega Mid_Ring ave/time 5 50 500 c_myChunk_omega[*] file tmp.myChunk_omega mode vector

compute myChunk_angmom Mid_Ring angmom/chunk Mid_Ring
fix Mid_Chunk_angmom Mid_Ring ave/time 5 50 500 c_myChunk_angmom[*] file tmp.myChunk_angmom mode vector

compute myChunk_torque Mid_Ring torque/chunk Mid_Ring
fix Mid_Chunk_torque Mid_Ring ave/time 5 50 500 c_myChunk_torque[*] file tmp.myChunk_torque mode vector

compute myChunk_inertia Mid_Ring inertia/chunk Mid_Ring
fix Mid_Chunk_inertia Mid_Ring ave/time 5 50 500 c_myChunk_inertia[*] file tmp.myChunk_inertia mode vector