抄録
In antiferroelectric smectic materials, it is expected that the tilt angle influences not only on stability of the antiferroelectric phase but also on the one of intermediate phases. The influences of the tilt angle θ and dipole-dipole interaction on the stabilitied of phases are studies on the base of the molecular interactions in smectics. It is shown that in the range of θ<θ_C, the behavior of XY-symmetry is stable, while in θ>θ_C the one of Ising-symmetry is stable.