Direct inner-shell photoionization of Xe atoms embedded in helium nanodroplets

• Published in: Journal of physics. B, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2020-10, Vol.53 (20), p.204001
• Main Authors: Ben Ltaief, L, Shcherbinin, M, Mandal, S, R Krishnan, S, Richter, R, Pfeifer, T, Mudrich, M
• Format: Article
• Language: English
• Subjects: Auger decay; charge transfer; Coulomb explosion; doped He nanodroplets; electron-ion coincidence spectroscopy; inner-shell photoionization; synchrotron radiation
• ISSN: 0953-4075; 1361-6455
• DOI: 10.1088/1361-6455/abaafb

We present the first measurements of photoelectron spectra of atomic clusters embedded in superfluid helium (He) nanodroplets. Owing to the large absorption cross section of xenon (Xe) around 100 eV photon energy (4d inner-shell ionization), direct dopant photoionization exceeds charge transfer ionization via the ionized He droplets. Despite the predominant creation of Xe2+ and Xe3+ by subsequent Auger decay of free Xe atoms, for Xe embedded in He droplets only singly charged Xek+, k = 1, 2, 3 fragments are observed. Broad Xe+ ion kinetic-energy distributions indicate Coulomb explosion of the ions due to electron transfer to the primary Auger ions from surrounding neutral atoms. The electron spectra correlated with Xe ions emitted from the He nanodroplets contain a low-energy feature and nearly unshifted Xe photolines. These results pave the way to extreme ultraviolet and x-ray photoelectron spectroscopy of clusters and molecular complexes embedded in He nanodroplets.