Regarding the msd for a crystalline solid structure

Dear Dr. Axel,

Thank you for resolving issues in lammps.

I am calculating msd for a crystalline solid undergoing thermal phase transition. In computing MSD, can you let me know using ‘com’ to ‘yes’ is correct or not. As, ‘com’= yes, the drift in centre of mass is subtracted out, but due to heating the centre of mass may change due to vibrational motions of the crystal structure(is this point valid?) and should using ‘com’=’yes’ correct in this context or not?

Kindly let me know about this.

Nanditha Sirigiri

Postgraduate student


Deakin University, Burwood Campus

Burwood Highway, Burwood 3125 Australia

computing an msd for a solid is a bit of a pointless exercise. there shouldn’t be any. it is a solid. same goes for removing a center of mass drift. there shouldn’t be any in the first place.