X-ray spectroscopy on size-selected clusters in an ion trap: from the molecular limit to bulk properties

Abstract

An experiment was designed to perform x-ray and VUV spectroscopy on size-selected clusters in the gas phase. Using a radio frequency ion trap and a quadrupole mass filter combined with an intense magnetron sputter source made it possible to record x-ray absorption spectra of mass-selected clusters in ion yield mode. These measurements clearly reveal the development from richly structured atomic spectra to bulk-like line shapes in transition metal clusters.

Spin and orbital magnetic moments of size-selected iron, cobalt, and nickel clusters

“…The 2p core hole that is created in the x-ray absorption process relaxes via Auger decay cascades. This leads to highly charged clusters, which disintegrate predominantly into monomer cations 63,66 that are also stored in the ion trap. Bunches of parent ions and product ions are extracted from the ion trap by a pulsed exit aperture potential, and are detected by a reflectron timeof-flight mass spectrometer with a mass resolution of m/∆m ≈ 3000 that operates in the inhomogeneous stray field of the superconducting solenoid and therefore is mounted in-line with the ion trap for maximum transmission.…”

Electronic ground states of Fe2+ and Co2+ as determined by x-ray absorption and x-ray magnetic circular dichroism spectroscopy

“…41 During formation, these ions are cooled to ≈ 150 K by multiple collisions with buffer gas atoms at p ≈ 1 mbar stagnation pressure. This allows for depopulation of excited states.…”

Photoionization study of Kr+and Xe+ions with the combined use of a merged-beam set-up and an ion trap

“…Recently, the same EBIT was used at BESSY II to record photoionization spectra of some multiply-charged ions [25]. Hirsch et al [26] have also used a linear trap at BESSY II to measure photoionization spectra of mass selected clusters. In this paper, we present our results on photoionization of Kr + and Xe + ions in the energy range covering 15 eV above the first ionization threshold, using both merged-beam and FT-ICR devices.…”