Photoelectron spectroscopy and zero electron kinetic energy spectroscopy of germanium cluster anions

Abstract

Anion photoelectron spectra of Ge n Ϫ , nϭ2-15, have been measured using an incident photon energy of 4.66 eV. In addition, the spectra of Ge 2 Ϫ , Ge 3 Ϫ , and Ge 4 Ϫ have been measured at photon energies of 3.49 and 2.98 eV. From these spectra the electron affinity of the corresponding neutral cluster has been determined. Vibrational frequencies and term values for several electronic states of Ge 2 Ϫ and Ge 3 Ϫ have been determined. Vibrational structure in the 3 B 3u excited state of Ge 4 has been resolved using zero electron kinetic energy ͑ZEKE͒ photoelectron spectroscopy. The assignment of the spectra of Ge 3 Ϫ and Ge 4 Ϫ is facilitated by a comparison to the similar spectra of Si 3 Ϫ and Si 4 Ϫ , respectively. The spectra of the larger clusters, Ge n Ϫ , nϭ5-15, are characterized by many broad structureless features which indicate the presence of multiple electronic transitions. Several of these were assigned based on comparison with previous ab initio calculations on germanium and silicon clusters.

Negative ions, mass selection, and photoelectrons

“…Again, mass-selected anion-PES is the method of choice here. Recent work from different laboratories includes studies, for instance, of gold (Handschuh et al, 1994b;Ganteför et al, 1992), mixed nickel (DixonWarren et al, 1996), silicon (Cheshnovsky et al, 1987b;Kitsopoulos et al, 1990;, or germanium (Burton et al, 1996a; clusters. For some of these studies, anion photoelectron spectroscopy and zero kinetic energy (ZEKE) photoelectron spectroscopy have both been used.…”

Chemical Applications of Zero Kinetic Energy (ZEKE) Photoelectron Spectroscopy

“…Neumark et al first applied the ZEKE method to photodetachment spectroscopy [64] and have been very active in this field. They have successfully performed studies on clusters of germanium, [154] silicon, [155] and halide ion molecules [156,157] as well as transition state complexes. [65] Their first ZEKE photodetachment spectrum was obtained in 1989 for the SH À anion (Figure 44).…”

Configuration Interaction Study of the Low-Lying Electronic States of GaBi

“…The jet-cooled GaAs has been studied by the resonant two-photon ionization spectroscopy. 7 Neumark and co-workers [8][9][10][11][12] have used the negative ion zero-electron kinetic photodetachment spectroscopic techniques to study the electronic states of the neutral group IV and group III-V clusters. Weltner and co-workers [13][14][15] have studied matrix-isolated electron-spinresonance (ESR) spectra of small clusters of Ga, Si, Sn, and mixed group III-V elements.…”