ABSTRACT
Niels Bohr developed his revolutionary theory of the hydrogen atom in 1913, still largely on classical terms. Then, in the 1920s, the generalization to other atoms and ions came with the development of quantum mechanics, or wave mechanics, by Schroedinger, Heisenberg and others, after de Broglie postulated that all elementary particles also have wave properties. Many highly precise spectroscopic data had been obtained experimentally, and these data could now be fully understood in terms of atomic structure and quantum numbers. Thus, laboratory and astrophysical spectra could for the first time be interpreted as specific classified transitions between energy levels of atoms or positive ions. William C. Martin and his colleagues Charles Corliss, Arlene Musgrove, Joseph Reader, Jack Sugar, and Romuald Zalubas maintained the high quality of the National Bureau of Standards work on the atomic energy level and wavelength tables and expanded and updated much of Charlotte Moore's work.
