Photoionization Yield Spectra below the Atomic Ionization Limit in Xenon

Abstract

Photocurrent yield and absorption spectra for xenon were measured as functions of pressure (p ^ 1 x 10 5 Pa) between -11.0 and 11.8 eV. With a pressure-independent yield function Y{hv) the photocurrent spectra can be calculated from the absorption spectra with the assumption of a "dead layer" at the surface of the LiF window. Y{hv) is roughly proportional to the number of atomic transitions with excitation energies between 11.10 eV and hv. This behavior can be explained with a simple statistical model for the decay of the Rydberg states.PACS numbers: 32.80.Fb, 33.80.EhRare gases are ideally suited to study basic processes in atomic and molecular systems. This includes Rydberg states, autoionization, dimer and excimer formation, and photoionization. A detailed knowledge of electronic excitation and the relaxation phenomena is of considerable theoretical interest but also has implications for the technical applications of rare gases, i.e., in excimer lasers and detectors. The ionization of rare gases has been studied recently by use of supersonic beams 1^3 and by multiphoton excitation with lasers. 4 Rare gases exhibit strong pressure effects in both fluorescence and ionization. Even at pressures as low as 40 Pa photoionization has been observed at photon energies that are considerably lower than the first atomic ionization potential of the rare-gas atoms. 5,6

Direct Observation of Microscopic Solvation at the Surface of Clusters by Ultrafast Photoelectron Imaging

“…This will be the case when the ions are much more solvated than the Rydberg states, resulting in a higher gap and a faster and more efficient autoionization. 47 The small difference in the autoionization efficiency that we observed between the free and the deposited molecule is an indication that the energy of the highly autoionizing Rydberg states is stabilized in a similar way to the ion in the cluster.…”

Vibrational autoionization of hot bands in methyl iodide

“…Here, hv is the excitation energy, CH3I represents a molecule in a Rydberg state, and e is the emitted electron. It should be noted that in this process, the maxima in the photoionization and in the absorption should coincide, unless strong absorption leads to "dead-layer" effects [6].…”