- Tunable isolated attosecond X-ray pulses with gigawatt peak power from a free-electron laser NATURE PHOTONICS 2020; 14 (1): 30-+
Attosecond transient absorption spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy.
Physical chemistry chemical physics : PCCP
The recent demonstration of isolated attosecond pulses from an X-ray free-electron laser (XFEL) opens the possibility for probing ultrafast electron dynamics at X-ray wavelengths. An established experimental method for probing ultrafast dynamics is X-ray transient absorption spectroscopy, where the X-ray absorption spectrum is measured by scanning the central photon energy and recording the resultant photoproducts. The spectral bandwidth inherent to attosecond pulses is wide compared to the resonant features typically probed, which generally precludes the application of this technique in the attosecond regime. In this paper we propose and demonstrate a new technique to conduct transient absorption spectroscopy with broad bandwidth attosecond pulses with the aid of ghost imaging, recovering sub-bandwidth resolution in photoproduct-based absorption measurements.
View details for DOI 10.1039/c9cp03951a
View details for PubMedID 31793561
- Observation of Bloch Oscillations in Molecular Rotation PHYSICAL REVIEW LETTERS 2015; 115 (20)
- Dynamical localization in molecular alignment of kicked quantum rotors PHYSICAL REVIEW A 2015; 92 (1)
Ultrafast isomerization initiated by X-ray core ionization.
2015; 6: 8199-?
Rapid proton migration is a key process in hydrocarbon photochemistry. Charge migration and subsequent proton motion can mitigate radiation damage when heavier atoms absorb X-rays. If rapid enough, this can improve the fidelity of diffract-before-destroy measurements of biomolecular structure at X-ray-free electron lasers. Here we study X-ray-initiated isomerization of acetylene, a model for proton dynamics in hydrocarbons. Our time-resolved measurements capture the transient motion of protons following X-ray ionization of carbon K-shell electrons. We Coulomb-explode the molecule with a second precisely delayed X-ray pulse and then record all the fragment momenta. These snapshots at different delays are combined into a 'molecular movie' of the evolving molecule, which shows substantial proton redistribution within the first 12 fs. We conclude that significant proton motion occurs on a timescale comparable to the Auger relaxation that refills the K-shell vacancy.
View details for DOI 10.1038/ncomms9199
View details for PubMedID 26354002