Autoionization states in xenon investigated by electron impact

Abstract

The inner-valence excitations of a xenon 5s electron were investigated by the electron impact method with an electron-energy-loss spectrometer. The incident energies of the electron beam are varied between 500 eV, 100 eV, 50 eV and 30 eV in order to assign the resonances in the spectra. Besides the optically allowed excitations normally observed by photoabsorption methods, lots of optically forbidden transitions were studied in the present work. The autoionization Rydberg series 5s−1ns, 5s−1np, 5s−1nd have been observed. Their energy levels, resonant profiles and quantum defects were obtained from the electron-energy-loss spectra. Other than single excitations, there are many double excitations in this energy region, which needs further sophisticated calculations and higher resolution experiments to assign most of the resonant features.

Attosecond Transient Absorption Explores Coupling Mechanisms of Autoionizing States

“…Our simulations suggest further that the intermediate state involved in the second quantum path is located at E 6p +ħω NIR = 22.51 eV. This even-parity intermediate state can be identified as the 5s5p 6 8s state, measured previously at 22.563 eV by electron impact [4]. Fig.…”

Investigation of coupling mechanisms in attosecond transient absorption of autoionizing states: comparison of theory and experiment in xenon

“…This finding strongly suggests that, for the oscillation to be visible in the absorption signal, the NIR detuning is required to be small and thus this coupling intermediate should be in the vicinity of E 6p + ħω NIR = 22.51 eV. This even-parity intermediate is thus identified as the 5s5p 6 8s state, measured previously at 22.563 eV by electron impact [26]. Even though this 8s state is dark from the ground state via a one-photon process, this analysis provides a way to both identify its parity and infer its location.…”

The role of absorption in large-angle elastic scattering

“…Interference between these channels causes the Fano line-shapes [16] with the characteristic dip before the peak. Using a small scattering angle (3 • ) and lower energies (30-500 eV) these states were investigated at high resolution by Yuan et al [17]. Their spectra showed large variations in intensities and shapes, and extrapolating to our measurement conditions is non-trivial.…”