Abstract
Generalizing our earlier results on the macroscopic dynamics close to the A to C* transition in smectic liquid crystals to higher frequencies in order to apply the approach to broadband dielectric spectroscopy, we find—in agreement with very recent experimental results—that there are only three dynamic modes in the frequency range up to 1 GHz and not four as suggested previously theoretically. We point out that the same number of modes (three) can be expected for the A—C transition in nonchiral materials where again the third mode is associated with rotations about the long axis of the rod-like molecules.