  Quantum mechanics thinks that atoms do not have permanent electric dipole
moment (EDM) because of their spherical symmetry. Therefore, there is no polar
atom in nature except for polar molecules. The electric susceptibility Xe
caused by the orientation of polar substances is inversely proportional to the
absolute temperature T while the induced susceptibility of atoms is temperature
independent. This difference in temperature dependence offers a means of
separating the polar and non-polar substances experimentally. Using special
capacitor our experiments discovered that the relationship between Xe of
Potassium atom and T is just Xe=B/T, where the slope B is approximately 283(K)
as polar molecules, but appears to be disordered using the traditional
capacitor. Its capacitance C at different voltage V was measured. The C-V curve
shows that the saturation polarization of K vapor has be observed when E more
than 105V/m and nearly all K atoms (over 98.9 per cent) are lined up with the
field! The ground state neutral K atom is polar atom with a large EDM: dK more
than 2.3*10-9e.cm.The results gave clear evidence for CP (charge conjugation
and parity) violation in K atoms. If K atom has a large EDM, why the linear
Stark effect has not been observed? The article discussed the question
thoroughly. Our results are easy to be repeated because the details of the
experiment are described in the article.
