On the Structure of the Helium Atom

(A. Landé. Das Serienspektrum des Heliums. Phys. ZS. 20, p. 228, 1919).

Bohr represents the model of the atom as follows: around the central positive nucleus, with two charges and a mass 4 times that of hydrogen, two electrons move in one common one-quantum circle, situated at the ends of one and the same diameter. Landé, in view of certain disagreements between theory and experiment, proposes another model, in which he places 2 electrons moving around the nucleus in different orbits. The first electron moves in a circle directly around the nucleus, and this orbit is one-quantum. The doubly charged nucleus and the moving electron constitute the central attracting mass for the second electron, which moves along an outer one-quantum circular orbit. The author avoids the difficulties of calculation by means of a number of additional assumptions, and as a result it turns out that Landé’s model, which gives better agreement with the optical data, proves to be more stable than Bohr’s former model; accordingly, the ionizing potential for Landé’s model must be greater than for Bohr’s model.

P. Lazarev.