ON COULOMB ENERGIES ANOMALOUS ISOTOPE SHIFT OF NUCLEAR RADII, AND CORE POLARIZATION BY NEUTRON EXCESS

Coulomb energy differences, obtained from isobaric analog states, were made the subject of a careful quantitative study in strings of isotopes with closed proton shells. The behavior of these energies with increasing neutron excess in Ca isotopes was found to differ qualitatively from that in the Ni or Sn isotopes. With measured values of charge radii, the Coulomb energy differences are used to deduce neutron radii and nuclear matter radii. It is concluded that the addition of f 7 2 neutrons in Ca does little to change the radius of the core of closed shells in 40Ca while the addition of neutrons in Ni and Sn polarizes the core appreciably. The trend in neutron and proton radii is similar in each of the three series of isotopes. © 1969.