Contribution of dechiralization lines to electro-optical response and dielectric permittivity in the SmC* phase

In the ferroelectric SmC* phase of antiferroelectric liquid crystal in plan ar geometry, a new contribution to the electro-optical and dielectric respo nses was found. This mode which we propose to be called a "surface layer mo de", appears with the apparition of 2 pi-disclinations (dechiralization lin es) in the texture. Some evidences of the existence of this mode are given. A simple model, taking into account a transformation of a pair of pi-discl ination on the surface to one 2 pi-disclination in the bulk is discussed.