Applications of resonance ionization spectroscopy in atomic and molecular physics

Resonance ionization spectroscopy (RIS) can be defined as a state-selective detection process in which pulsed tunable lasers are used to promote transitions from the selected state of the atoms or molecules in question to higher states, one of which will be ionized by the further absorption of another photon. At least one resonance step is used in the stepwise ionization process, and it has been shown that the ionization probability of the spectroscopically selected species can nearly always be made close to unity. The ability to make saturated RIS measurements opens up a wide array of applications to both basic and applied research. The chapter discusses applications of RIS methods to atomic and molecular physics. It begins with a theoretical description of multiphoton excitation using broad bandwidth lasers with a twofold purpose. First, the theoretical results are used to estimate excitation probabilities with regard to the feasibility and expected signal magnitude of the experiments discussed. Second, the results of these experiments can, in turn, be used to test various aspects of the theory such as atomic structure calculations and the model chosen to describe the laser radiation. A variety of photophysics and collision physics experiments on inert gases are suggested and described. The results of an experiment on the two-photon excitation of Xe are also discussed in the chapter. The possible use of RIS techniques in conjunction with pulsed supersonic nozzle jet beams is illustrated with the proposal of a couple of experiments.