ABSTRACT
Although the theory of Bohr sufficed to interpret the spectral lines associated with
elemental hydrogen, which had been excited by a flame, the extension of this
theory to entirely explain the line spectra of heavier atoms proved to be
elusive. In addition, an explanation for the doubling of lines in the hydrogen spec-
trum eluded the simple theory. As indicated in the last chapter, only the wave
mechanical theories of Schro¨dinger, Heisenberg, and Dirac were able to
provide the necessary mathematical description of atomic structure that permitted
physicists to adequately interpret the empirical data that had become widely
available. It became obvious to these workers that an understanding of the
spectroscopy of atomic and molecular states derived from core electrons in a mol-
ecule required the development of a comprehensive picture for the quantum
numbers that define such states. The solution to the wave mechanical equation
of the hydrogen atom was found to meet this need, because it could be solved
exactly. Furthermore, its solutions would then be used to develop approximate
treatments for heavier atoms.
