Double-core-hole spectroscopy for chemical analysis with an intense X-ray femtosecond laser
2011 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, no 41, 16912-16915 p.Article in journal (Refereed) Published
Theory predicts that double-core-hole (DCH) spectroscopy can provide a new powerful means of differentiating between similar chemical systems with a sensitivity not hitherto possible. Although DCH ionization on a single site in molecules was recently measured with double-and single-photon absorption, double-core holes with single vacancies on two different sites, allowing unambiguous chemical analysis, have remained elusive. Here we report that direct observation of double-core holes with single vacancies on two different sites produced via sequential two-photon absorption, using short, intense X-ray pulses from the Linac Coherent Light Source free-electron laser and compare it with theoretical modeling. The observation of DCH states, which exhibit a unique signature, and agreement with theory proves the feasibility of the method. Our findings exploit the ultrashort pulse duration of the free-electron laser to eject two core electrons on a time scale comparable to that of Auger decay and demonstrate possible future X-ray control of physical inner-shell processes.
Place, publisher, year, edition, pages
2011. Vol. 108, no 41, 16912-16915 p.
multi-photon ionization, ultrafast, two-photon spectroscopy
IdentifiersURN: urn:nbn:se:uu:diva-161042DOI: 10.1073/pnas.1111380108ISI: 000295973800015OAI: oai:DiVA.org:uu-161042DiVA: diva2:456631