Soft X-ray Absorption Spectroscopy of Aqueous Solutions Using a Table-Top Femtosecond Soft X-ray Source

Abstract

We demonstrate the feasibility of soft X-ray absorption spectroscopy in the water window using a table-top laser-based approach with organic molecules and inorganic salts in aqueous solution. A high-order harmonic source delivers femtosecond pulses of short wavelength radiation in the photon energy range from 220 to 450 eV. We report static soft X-ray absorption measurements in transmission on the solvated compounds O=C(NH 2 ) 2 , CaCl 2 , and NaNO 3 using flatjet technology. We monitor the absorption of the molecular samples between the carbon (∼280 eV) and nitrogen (∼400 eV) K-edges and compare our results with previous measurements performed at the BESSYII facility. We discuss the roles of pulse stability and photon flux in the outcome of our experiments. Our work paves the way toward table-top femtosecond, solution-phase soft X-ray absorption spectroscopy in the water window.

Vibronic Dynamics of Photodissociating ICN from Simulations of Ultrafast X‐Ray Absorption Spectroscopy

“…Spectral broadening with FWHM >4.5 V masks the dynamical information of the photodissociation process by merging all peaks into a broad band centered at 295 eV. Since a spectral resolution of ≤1.2 eV at the carbon K‐edge has already been reported for current laser‐based table‐top UV/X‐ray pump–probe setups (utilizing extreme high‐order harmonic radiation and with clear options for further improvements) [16] and resolution at large scale facilities is about an order of magnitude better, [2b, 17] measuring the predicted oscillatory features should be clearly within experimental reach.…”

High-repetition-rate ( kHz) targets and optics from liquid microjets for high-intensity laser–plasma interactions

“…e self-refreshing nature of the targets would present them as ideal for destructive or consumable operation in studies of high harmonic generation [109][110][111][112][113] , shock dynamics [114][115][116] , and X-ray free electron laser irradiation [117][118][119] . e submicron thickness of the sheet target con guration would suggest its use in research of so X-ray spectroscopy [120][121][122] , interfacial and surface chemistry [123] , and even positron scattering [124,125] . Future research and development of liquidbased, vacuum compatible targets and optics will increase the already numerous potential applications.…”

Ultrafast photoinduced energy and charge transfer

“…This was achieved in closed cells by Huse and co-workers, 120,121 but novel liquid sample delivery schemes under vacuum, [122][123][124] are now opening the eld. 125 In addition to the above X-ray spectroscopies, we should also mention another core-level spectroscopy: X-ray photoelectron spectroscopy (XPS), which allows element-selective detection along with the absolute binding energies of given orbitals. [126][127][128][129] While its extension to solutions has been achieved for some years now 122,[129][130][131][132][133] it has mostly been used for studies of ET (or electron injection) of sensitized systems, for which they are actually an ideal tool.…”