Classical theory of the chaotic ionization of highly excited hydrogen atoms

Over the past decade, classical mechanics has been transformed from an historical relic into a contemporary model for certain problems in atomic and molecular physics. This transformation has been brought about by recent interest in the study of chaotic dynamics in nonlinear classical systems. A good example is the behavior of highly excited atoms in microwave fields. In the language of classical mechanics a hydrogen atom in a microwave field is a periodically perturbed nonlinear oscillator. Depending on the strength of the perturbing microwave field, the equations of motion can become chaotic. The chaotic electron dynamics results in rapid ionization above a threshold microwave field strength. This paper presents the basic components of the classical models that we have introduced to describe this chaotic ionization of highly excited hydrogen atoms. (C) 1996 American Association of Physics Teachers.