orienting potential versus molecular difframe

[Ntasha]

Hello,
Can the orienting potential and molecular difframe be used interchangeably in lipid bilayers or other systems that constrain the angle of a probe movement? If not, what is the difference? If yes, what is the advantage of using one versus the other?
Thanks

[Stefan Stoll]

These are fundamentally different models. If you specify an orienting potential, then you are restricting the motional range of the probe. On the other hand, rotating the molecular diffusion frame just changes the principal rotational diffusion directions of the probe, without restricting the motion at all.

If you are in a lipid bilayer and the motion is restricted, I think it's best to use a (simple) orienting potential.