Rostock 2019 – scientific programme
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MO: Fachverband Molekülphysik
MO 8: XUV and X-ray Excitation and Spectroscopy
MO 8.1: Talk
Monday, March 11, 2019, 16:15–16:30, S HS 001 Biologie
Time domain measurement of the ultrafast electronic decay of core excited HCl molecules by THz streaking — •Katharina Wenig1, Marek Wieland1, Sophie Walther1, Arne Baumann1, Anastasios Dimitriou1, Mark Prandolini1, Oliver Schepp1, Ivette Bermùdez Macias1, Malte Sumfleth1, Nikola Stojanovic2, Stefan Düsterer2, Juliane Röntsch-Schulenburg2, Markus Drescher1, and Ulrike Frühling1 — 1Institut für Experimentalphysik, Universität Hamburg, Deutschand — 2Deutsches Elektron-Synchrotron DESY, Hamburg, Deutschalnd
After excitation of 2p core electrons to the antibonding σ* orbital the HCl molecules dissociate and the electronic excitation relaxes via an Auger decay. We have measured the ultrafast electronic decay of HCl molecules in the time domain.
In the experiment we adressed the 2p core electrons with 40 fs (FWHM) soft x-ray pulses from the free-electron laser in Hamburg (FLASH). Superimposing the pump pulse with intense THz light electrons emitted from the molecules are accelerated (streaked) by the THz electric field. Thereby, the resulting momentum change of the electron depends on the THz phase at the instant of ionization. We were able to measure the phase shift between the photo- and Auger electrons in the THz streak spectrograms and determine the Auger decay constant of the HCl molecule. In order to verify the resolution of our experiment the MNN Auger decay of Krypton atoms was investigated as well. The accuracy of the extraced value is on the order of two femtoseconds and therefore much below the duration of the exciting pump pulse.