Electronic Polarizabilities of Ions in Crystals

A set of electronic polarizabilities has been obtained from a least-squares fit of experimental refraction data using simple additivity and a Lorentz factor of 43. Except for the fluorides, the electronic polarizability values of the alkali-halide crystals calculated from this set agree with the experimental data within 3 percent. Similar least-squares fits were attempted with various values of the Lorentz factor, the best fit being obtained for 43. On the basis of 43, the additivity assumption and the alkali-halide set, polarizabilities have been obtained for other ions. The best values for the sodium D line in A^3 are Li^+ 0. 03, Na^+ 0. 41, K^+ 1. 33, Rb^+ 1. 98, Cs^+ 3. 34, F^- 0. 64, Cl^- 2. 96, Br^- 4. 16, I^- 6. 43, Ca^++ 1. 1, Sr^++ 1. 6, Ba^++ 2. 5, O^-- 0. 5-3. 2, S^-- 4. 8-5. 9, Se^-- 6. 0-7. 5, Te^-- 8. 3-10. 2, Ag^+ 2. 4, Cu^+ 1. 6, Cu^++ 0. 2, Zn^++ 0. 8, Cd^++ 1. 8, Ge^4+ 1, Sn^4+ 3. 4, Pb^++ 4. 9. Values represented by a spread indicate ions that cannot be treated additively.