William Draper Harkins (28.12.1873 — 7.03.1951) was an American physicist and chemist and a member of the National Academy of Sciences. He was born in Titusville. He graduated from Stanford University (1900). In 1912 — 39 he worked at the University of Chicago (professor from 1917).
His work concerned nuclear chemistry and nuclear physics (the study of atomic structure, the stability of nuclei and the abundance of the chemical elements in the Universe) and the chemistry of surface phenomena. He showed that an enormous energy is released when hydrogen nuclei combine in a helium nucleus. He introduced the concepts of the “packing effect” and the “packing fraction”. In 1917 he came to the conclusion that nuclei with an even atomic number are more stable and occur more often than those with an odd one. He put forward the idea of nuclear periodicity. He predicted the existence of the neutron (1920) and of deuterium, heavy hydrogen. He obtained formulas and gave tables of the composition of light nuclei, and introduced the concept of even-even and even-odd nuclei (1920). He was one of the first to carry out (1932) nuclear reactions under the action of neutrons. He proposed a possible mechanism for the production of energy in stars. He studied surface phenomena, in particular measuring surface tension.
J. Gibbs Medal (1928).