Formation probability of metastable molecular hydrogen anions H _mD _n ⁻ (m, n = 0–3 and m + n = 2, 3) in sputtering

Autor(en)

Hubert Gnaser, Robin Golser

Abstrakt

The formation of molecular hydrogen anions (H-2(-), D-2(-), HD-, H-3(-), HD2-, and D-3(-)) was investigated. These anion species were produced by sputtering of TiD2 and HfH2 targets with Cs+ ions and were identified by secondary-ion mass spectrometry (SIMS), yielding the corresponding abundance distributions. The intensity ratios of both the diatomic (HD-/D-2(-)) and triatomic (HD2-/D-3(-)) molecular ions are (distinctly) lower than what would be expected from the respective statistical isotopic pattern. This observation indicates that the different lifetimes of these metastable anions are decisive for their formation probability in sputtering and their survival in the mass spectrometer. In addition to molecular ions, the isotopic fractionation of the atomic hydrogen ions, D-/H-, was determined. A strong depletion of the heavier D isotope in the sputtered ion flux by (47.0 +/- 3.1)% was found. This pronounced isotope fractionation could be due to a velocity-dependence of the ionization probability, amplified by the large mass difference of the hydrogen isotopes.

Organisation(en)

Isotopenphysik

Externe Organisation(en)

Technische Universität Kaiserslautern, Institut für Oberflächen- und Schichtanalytik GmbH, Kaiserslautern

Journal

International Journal of Mass Spectrometry

Band

410

Seiten

52-56

Anzahl der Seiten

5

ISSN

1387-3806

DOI

https://doi.org/10.1016/j.ijms.2016.11.004

Publikationsdatum

11-2016

Peer-reviewed

Ja

ÖFOS 2012

103014 Kernphysik

Schlagwörter

ASJC Scopus Sachgebiete

Condensed Matter Physics, Instrumentation, Spectroscopy, Physical and Theoretical Chemistry

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/d308abb1-dab6-4c07-8386-a83a2749b49e