entering in Rydberg’s formula is the same for all substances.
Let us assume that the spectrum in question corresponds to the radiation emitted during the binding of an electron; and let us further assume that the system including the electron considered is neutral. The force on the electron, when at a great distance apart from the nucleus and the electrons previously bound, will be very nearly the same as in the above case of the binding of an electron by a hydrogen nucleus. The energy corresponding to one of the stationary states will therefore for
great be very nearly equal to that given by the expression (3) on [p. 5], if we put
. For
great we consequently get
in conformity with Rydberg’s theory.