title: Analysis of a measurement scheme for ultrafast hole dynamics by few femtosecond resolution X-ray pump-probe Auger spectroscopy.
abstract: Ultrafast hole dynamics created in molecular systems as a result of sudden ionisation is the focus of much attention in the field of attosecond science. Using the molecule glycine we show through ab initio simulations that the dynamics of a hole, arising from ionisation in the inner valence region, evolves with a timescale appropriate to be measured using X-ray pulses from the current generation of SASE free electron lasers. The examined pump-probe scheme uses X-rays with photon energy below the K edge of carbon (275-280 eV) that will ionise from the inner valence region. A second probe X-ray at the same energy can excite an electron from the core to fill the vacancy in the inner-valence region. The dynamics of the inner valence hole can be tracked by measuring the Auger electrons produced by the subsequent refilling of the core hole as a function of pump-probe delay. We consider the feasibility of the experiment and include numerical simulation to support this analysis. We discuss the potential for all X-ray pump-X-ray probe Auger spectroscopy measurements for tracking hole migration.
authors.affiliation: Imperial College, Blackett Laboratory, Prince Consort Road, London, SW7 2BB, UK. b.cooper@imperial.ac.uk.
authors.forename: Bridgette
authors.initials: B
authors.lastname: Cooper
authors.forename: Přemysl
authors.initials: P
authors.lastname: Kolorenč
authors.forename: Leszek J
authors.initials: LJ
authors.lastname: Frasinski
authors.forename: Vitali
authors.initials: V
authors.lastname: Averbukh
authors.forename: Jon P
authors.initials: JP
authors.lastname: Marangos