Determination of same changes in rotational potentials between ferro-and antiferroelectric phases

Rotational potential of molecule in smectic phases, introduced by Zeks, includes two important parts: dipolar as well as quadrupolar ones. The first part is valid for chiral molecules only, whereas the second one is important for chiral and achiral molecules. The question arises: "Whether shape of rotational potential changes when the phase transition between SmC* and SmCA* appears?" In our opinion, close to the temperature of phase transition (FLC-AFLC) magnitudes of both, dipolar and quadrupolar parts change. Quadrupolar coupling is more important for antiferroelectric phase, while dipolar factor overwhelms quadrupolar one, for ferroelectric phase.