Theory of ZEKE spectroscopy and molecular Rydberg dynamics

We review some of the theor. techniques developed in the past decade to study ZEKE spectroscopy and dynamics. These techniques can be used to calc. not only the transition energies and the spectral intensities but also the dynamical quantities, such as radiative lifetimes, autoionization and collision cross sections, of high Rydberg states. Both aspects of spectroscopy and dynamics are discussed and are mainly based on our previous research results. Using the inverse Born-Oppenheimer approxn. (IBOA) as a basis set, we have calcd. the absorption rates for the resonance two-photon (R2P) and non-resonance two-photon (NR2P) zero kinetic energy (ZEKE) or mass analyzed threshold ionization (MATI) spectroscopy. The resonance VUV-IR and IR-VUV two-photon spectra are discussed sep. to emphasize their resp. applications. For comparison, the formulas to analyze the recently proposed one-photon (1P) ZEKE spectroscopy are also presented using the IBOA. To study the Rydberg dynamics, we have calcd. the spontaneous emission rates and the blackbody radiation induced transition rates to establish a ref. time scale for high Rydberg states. Due to the large size of a Rydberg atom, the inelastic collision cross sections are significant. We have thus calcd. the cross sections for a Rydberg atom in collision with an ion using the Born approxn. We also show how to calc. the transition probabilities of autoionization due to the breakdown of the IBOA. To analyze both the vibronic spectra and dynamical quantities for Rydberg mols., we employ quantum chem. calcn. to obtain the potential surfaces of mols. and their ions. These potential surfaces can then be used to calc. the Franck-Condon factors involved in the vibronic transitions. Several exptl. spectra are analyzed with this theory. [on SciFinder(R)]     «

We review some of the theor. techniques developed in the past decade to study ZEKE spectroscopy and dynamics. These techniques can be used to calc. not only the transition energies and the spectral intensities but also the dynamical quantities, such as radiative lifetimes, autoionization and collision cross sections, of high Rydberg states. Both aspects of spectroscopy and dynamics are discussed and are mainly based on our previous research results. Using the inverse Born-Oppenheimer approxn. (I...     »