Investigation of electron correlation effects in the inner-valence photoelectron spectra of argon and xenon using synchrotron radiation at high resolution

Abstract

High-resolution, magic angle photoelectron spectra have been obtained for the Ar 3 s and Xe 5s inner-valence regions using photon energies in the range 60-170 eV. Measurements were made using monochromatized synchrotron radiation from the Canadian Synchrotron Radiation Facility at the new 1-GeV storage ring at the University of Wisconsin. The binding energy spectra show detailed and complex structures due to electron correlation (many-body) effects. Relative satellite intensities are compared with the results of recent configuration-interaction calculations. Additional binding energy spectra obtained at much higher resolution (0.16 eV fwhm) than any previous published work show extremely detailed satellite structure consistent with information from recent high resolution fluorescence studies for argon. The newly revealed satellite structure provides further insight into existing differences between calculated and measured satellite intensities. In the case of the Ar 3s spectrum, very close agreement is predicted between the measured intensities and those calculated by CI methods when the previously unresolved satellite structure is taken into account. These new spectral observations also provide information and perspective relevant to recent controversies in the literature concerning intensities and mechanisms in photoelectron and electron momentum spectroscopies. obtenus i une rCsolution beaucoup plus grande (0,16 eV fwhm) que celles utilisees anterieurement, presentent une structure satellite extrgmement detaillee qui est en accord avec l'information obtenue a partir d'etudes recentes de fluorescence a haute resolution effectukes sur l'argon. La nouvelle structure satellite observee fournit une connaissance plus profonde sur les differences qui existent entre les intensites satellites calcultes et mesurkes. Dans le cas du spectre du Ar 3s, alors qu'on prend en consideration la structure satellite qui n'avait pas etk rksolue anterieurement, on observe une excellente correlation entre les intensites mesurees et celles calcul&es par les mkthodes des IC. Ces nouvelles observations spectrales fournissent aussi de l'information et une perspective qui presentent de l'intCr2t en relation avec les rkcentes controverses qui ont surgies dans la litterature concernant les intensites et les mecanismes des spectroscopies phototlectronique et du moment Clectronique.[Traduit par la revue] Introduction Photoelectron spectroscopy (PES) using vacuum ultraviolet radiation has provided detailed insight into valence-shell photoionization processes and the electronic structure of free atoms and molecules. Early He1 PES studies of the outer-valence np photoionization of the noble gases by Al-Joboury and Turner (1, 2), and also the elegant photoelectron studies of Ar, K r , and Xe by Frost, McDowell, and Vroom (3), using a spherical grid retarding spectrometer were seminal in the rise and development of ultraviolet PES. Today PES is a precise tool not only for the study of fundamental processes in photoionization, but also for the inv...

Satellite structure of the xenon valence shell by electron-momentum spectroscopy

“…This intensity cannot therefore belong to the 5s manifold. High-resolution syn-chrotron [8] and x-ray photoelectron spectra [6] show a satellite peak at 25.3 eV of the same intensity as the 24.67 eV transition. Furthermore, they also show a transition at 26.6 eV with similar intensity.…”

“…5 Ss manifold cross section. Thus any Sp satellite (8) 400where the spherical average is due to the random orientation of the target atoms or molecules in a gas target.…”

“…1). The results are given in Table II, where they are also compared with two recent (y, e) results [6,8] and a recent theoretical calculation [20].…”

“…Figure 5(b) shows that the 5p momentum distribution indeed gives an excellent fit to the data, both in shape and in magnitude, when multiplied by the factor of 0.02. These transitions have normally been mistakenly assigned to the 5s manifold in PES work [6,8,9]. They were, however, tentatively identified by Hansen and Persson [18] as belonging to the Sp manifold on the basis of PES satellite intensity measurements at low photon energy [24,25].…”

Optical threshold excitation functions of Xe 5s,5pphotoionization satellites near the 5s−1Cooper minimum

“…Studies of Xe satellites as a fascinating showcase of electron correlation were made of the inner-4d-shell ionization [1][2][3][4]. However, because of a photoionization cross section of the Xe Ss shell around the double-ionization limit in its Cooper-minimum region [5], intensity ratios of satellites to the principal s ' state in this region [6,7] were remarkably large in comparison with those well above the threshold [8]. This was also the case for Ar 3s satellites [9].…”