Nuclear Shell Structure

Abstract

As early as 1917 Harkins (17) pointed out that nuclei with even numbers of protons or neutrons are more stable than those with odd numbers. Elsasser (33, 34) found that special numbers of protons or neutrons form particularly stable configurations. We shall list here a series of facts which indicate that we obtain especially stable nuclei when either the number of protons Z or the number of neutrons N = A – Z is equal to one of the following numbers (Mayer 48): $$2,\;8,\;14,\;20,\;28,\;50,\;82,\;126$$ (1) These values are commonly referred to as magic numbers.