Magnetic Fields and Rotational Diffusion

[Thadis]

Hello, I am having to find the rotational diffusion of a magnetic particle inside of water. I already have a diffusion coefficient but I do not know how to take into account the restoring force that the particle will feel from the magnetic field.

The info that I know is:
B-Field Strength
m-magnetic moment
D-rotational diffusion coeffiecent

I have been using the online program Hydra++ to get the rotational diffusion coeffiencent.

Does anyone know how to take into account the restoring force of the magnetic field? Thank you.

 

[Jano L.]

The particle will experience torque (moment of force)

$$
\boldsymbol{\tau} = \mathbf m  \times \mathbf B
$$