Irreducible Susceptibilities and Their Application to Rochelle Salt

Any vector-patterns defined in a unit cell of a crystal can always be decomposed into irreducible patterns. Between an irreducible pattern of dipole moment and an irreducible component of electric field with the same label of irreducible representation, a new concept of irreducible susceptibility can be defined. The inherent structure of the Mitsui theory of Rochelle salt has been reexamined in the light of this new concept and the meaning of its two-sublattice model has been clarified.