As an atomic physicist, I have been interested primarily in tests of fundamental interactions and in explorations of atoms that are unusual in regard to their degree of excitation or particle composition. These investigations include, among others:

• The combination of accelerator technology and radiofrequency spectroscopy to make a fast atomic beam for precision fine and hyperfine spectroscopy of atomic hydrogen. The use of a fast atomic beam permitted spectroscopy and charge-exchange collisional studies to be performed on short-lived excited states under well-defined conditions largely free from extraneous fields.
  • In the book Probing The Atom
• I developed a comprehensive theory of the interaction of atoms with radiofrequency, microwave, and optical fields to predict single- and multi-photon spectroscopic lineshapes from which detailed information could be extracted concerning atomic structure and interactions.
  • In the book Probing The Atom
• I investigated highly excited atomic states (Rydberg states) by means of laser-induced quantum interference in the time domain. The general theory of laser-induced quantum beats predicted novel nonlinear effects as well as the quantum beat signals of atoms subjected to external static fields.
  • In the books More Than One Mystery, Quantum Superposition
• An exotic atom is one in which a bound electron is replaced by an unstable particle. I have examined theoretically the properties of muonic atoms in strong magnetic fields and the consequences of quantum statistics on the lifetime of the dimuon atom, a prototype of an entirely new class of hitherto unexamined atomic species.
  • In the book And Yet It Moves