  Since the time of Rutherford 1911) physicists and chemists commonly believed
that with no electric field, the nucleus of an atom is at the centre of the
electron cloud, atoms do not have permanent electric dipole moment (EDM), so
that there is no polar atom in nature. In the fact, the idea is untested
hypothesis. After ten years of intense research, our experiments showed that
atoms can be divided into three categories: polar, non-polar and hydrogen atom.
Alkali atoms are all polar atoms. The EDM of a Sodium, Potassium, Rubidium and
Cesium atom in the ground state have been obtained as follows: d(Na)=1.28*10
to-8 power e.cm; d(K)=1.58*10 to-8 power e.cm; d(Rb)=1.70 *10 to-8 power e.cm;
d(Cs)=1.86*10 to-8 power e.cm. All kind of atoms are non-polar atoms except for
alkali and hydrogen atoms. Hydrogen atom is quite distinct from the others. The
ground state in hydrogen is non-polar atom(d=0) but the excited state is polar
atom, for example, the first excited state has a large EDM: d(H)=3ea=1.59*10
to-8 power e.cm (a is Bohr radius).
