With cell model,the polarized order parameter is defined on cell center.By choice of interaction potential of biaxial molecules possessing a permanent electris dipole moment transverse to molecular axes,the system free energy is obtained.The approximate formula of spontaneous polarization and pitch is derived by calculation of variation to the free energy.We have calculated the temperature and the molecular transverse electric dipole dependence of the spontaneous polarization and pitch for four classic SmC* liquid crystals of DOBAMBC and 3M2CPOOB etc.The calculations agree satisfactorily with experimental results.It is shown that the spontaneous polarization is mainly due to the molecular biaxiality and transverse electric dipole of the SmC* liquid crystals.
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