N=3. Lithium.
In analogy with the cases of hydrogen and helium we must expect that during the binding of an electron by a nucleus of charge
, a spectrum is emitted, given by
On account of the great energy to be spent in removing all the electrons bound in a lithium atom (see below) the spectrum considered can only be expected to be observed in extraordinary cases.
In a recent note Nicholson[34] has drawn attention to the fact that in the spectra of certain stars, which show the Pickering spectrum with special brightness, some lines occur the frequencies of which to a close approximation can be expressed by the formula
where
