Thanks for the answer.

But I want to calculate the quaternion from angular velocity and calculate the rotational diffusion coefficient using the quaternions. I went to Python because I couldn’t find a way to do it in Lammps. In Python using function in the package pydiffusion. I was able to compute quaternion using angular velocity. But in this function there is a difference between the angular velocity in the center of mass of the object and the angular velocity in the coordinate of the laboratory.

So I want to know the omega chunck output in lammps are in center of mass coordinates or in lab coordinates .

The function is as follows:

def calc_quat(omega, q0, rate, CStype):

‘’’

Take an angular velocity (in rad/s), and convert it into the

corresponding orientation quaternion.

Parameters