R. Moshammer
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View article: Dynamics of highly-ionised Diiodomethane: Coulomb Explosion, Energy Exchange and Rotating Fragments
Dynamics of highly-ionised Diiodomethane: Coulomb Explosion, Energy Exchange and Rotating Fragments Open
The dissociation dynamics of diiodomethane molecules (CH2I2) have been investigated following absorption of 98 eV XUV photons. In the measurement at the reaction microscope endstation at the free-electron laser FLASH2, ionic fragments crea…
View article: Redirection and Reshaping of Intense Extreme-Ultraviolet Radiation
Redirection and Reshaping of Intense Extreme-Ultraviolet Radiation Open
The goal to control short-wavelength radiation for the investigation and manipulation of ultrafast dynamics in quantum systems coevolves with the growing availability of extreme-ultraviolet (XUV) and x-ray sources from high-harmonic genera…
View article: Formation of singly ionized oxygen atoms from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math> driven by XUV pulses: A toolkit for the breakup of free-electron-laser-driven diatomics
Formation of singly ionized oxygen atoms from driven by XUV pulses: A toolkit for the breakup of free-electron-laser-driven diatomics Open
We formulate a general hybrid quantum-classical technique to describe the interaction of diatomic molecules with XUV pulses. We demonstrate the accuracy of our model in the context of the interaction of the O2 molecule with an XUV pulse wi…
View article: Symmetry-breaking dynamics of a photoionized carbon dioxide dimer
Symmetry-breaking dynamics of a photoionized carbon dioxide dimer Open
Photoionization can initiate structural reorganization of molecular matter and drive formation of new chemical bonds. Here, we used time-resolved extreme ultraviolet (EUV) pump - EUV probe Coulomb explosion imaging of carbon dioxide dimer …
View article: Formation of singly ionized oxygen atoms from O$_2$ driven by XUV pulses: a toolkit for the break-up of FEL-driven diatomics
Formation of singly ionized oxygen atoms from O$_2$ driven by XUV pulses: a toolkit for the break-up of FEL-driven diatomics Open
We formulate a general hybrid quantum-classical technique to describe the interaction of diatomic molecules with XUV pulses. We demonstrate the accuracy of our model in the context of the interaction of the O$_2$ molecule with an XUV pulse…
View article: Multi-sideband interference structures by high-order photon-induced continuum-continuum transitions in helium
Multi-sideband interference structures by high-order photon-induced continuum-continuum transitions in helium Open
Following up on a previous paper on two-color photoionization of Ar(3p) [D. Bharti , ], we present measurements and calculations for a modified three-sideband (3-SB) version of the reconstruction of attosecond beating by interference of tw…
View article: Sub-50 fs temporal resolution in an FEL-optical laser pump-probe experiment at FLASH2
Sub-50 fs temporal resolution in an FEL-optical laser pump-probe experiment at FLASH2 Open
High temporal resolution is essential for ultra-fast pump-probe experiments. Arrival time jitter and drift measurements, as well as their control, become critical especially when combining XUV or X-ray free-electron lasers (FELs) with opti…
View article: Time-resolving state-specific molecular dissociation with XUV broadband absorption spectroscopy
Time-resolving state-specific molecular dissociation with XUV broadband absorption spectroscopy Open
The electronic and nuclear dynamics inside molecules are essential for chemical reactions, where different pathways typically unfold on ultrafast timescales. Extreme ultraviolet (XUV) light pulses generated by free-electron lasers (FELs) a…
View article: Multi-sideband interference structures by high-order photon-induced continuum-continuum transitions in helium
Multi-sideband interference structures by high-order photon-induced continuum-continuum transitions in helium Open
Following up on a previous paper on two-color photoionization of Ar(3p) [Bharti et al., Phys. Rev. A 103 (2021) 022834], we present measurements and calculations for a modified three-sideband (3-SB) version of the "reconstruction of attose…
View article: Influence of nuclear dynamics on molecular attosecond photoelectron interferometry
Influence of nuclear dynamics on molecular attosecond photoelectron interferometry Open
In extreme ultraviolet spectroscopy, the photoionization process occurring in a molecule due to the absorption of a single photon can trigger an ultrafast nuclear motion in the cation. Taking advantage of attosecond photoelectron interfero…
View article: Velocity Map Imaging with No Spherical Aberrations
Velocity Map Imaging with No Spherical Aberrations Open
Velocity map imaging (VMI) is a powerful technique that allows to infer the kinetic energy of ions or electrons that are produced from a large volume in space with good resolution. The size of the acceptance volume is determined by the sph…
View article: Direct tracking of ultrafast proton transfer in water dimers
Direct tracking of ultrafast proton transfer in water dimers Open
Upon ionization, water forms a highly acidic radical cation H 2 O +· that undergoes ultrafast proton transfer (PT)—a pivotal step in water radiation chemistry, initiating the production of reactive H 3 O + , OH radicals, and a (hydrated)…
View article: Ultrastable, high-repetition-rate attosecond beamline for time-resolved XUV–IR coincidence spectroscopy
Ultrastable, high-repetition-rate attosecond beamline for time-resolved XUV–IR coincidence spectroscopy Open
The implementation of attosecond photoelectron–photoion coincidence spectroscopy for the investigation of atomic and molecular dynamics calls for a high-repetition-rate driving source combined with experimental setups characterized by exce…
View article: Isotopic effects in molecular attosecond photoelectron interferometry
Isotopic effects in molecular attosecond photoelectron interferometry Open
Isotopic substitution in molecular systems can affect fundamental molecular properties including the energy position and spacing of electronic, vibrational and rotational levels, thus modifying the dynamics associated to their coherent sup…
View article: Multisideband interference structures observed via high-order photon-induced continuum-continuum transitions in argon
Multisideband interference structures observed via high-order photon-induced continuum-continuum transitions in argon Open
We report a joint experimental and theoretical study of a three-sideband (3-SB) modification of the reconstruction of attosecond beating by interference of two-photon transitions (RABBIT) setup. The 3-SB RABBIT scheme makes it possible to …
View article: Laser control of an excited-state vibrational wave packet in neutral H$_2$
Laser control of an excited-state vibrational wave packet in neutral H$_2$ Open
We observe and control a molecular vibrational wave packet in an electronically excited state of the neutral hydrogen molecule. In an extreme-ultraviolet (XUV) transient-absorption experiment we launch a vibrational wave packet in the $D ^…
View article: Velocity map imaging with no spherical aberrations
Velocity map imaging with no spherical aberrations Open
An analytical derivation for achieving velocity map imaging (VMI) with no spherical aberations is described. Simulations show how this method can be used for operating the CSR-ReMi in a VMI mode with an extremely large source volume.
View article: Controlling Fragmentation of the Acetylene Cation in the Vacuum Ultraviolet via Transient Molecular Alignment
Controlling Fragmentation of the Acetylene Cation in the Vacuum Ultraviolet via Transient Molecular Alignment Open
An open-loop control scheme of molecular fragmentation based on transient molecular alignment combined with single-photon ionization induced by a short-wavelength free electron laser (FEL) is demonstrated for the acetylene cation. Photoele…
View article: Ultrastable, high-repetition-rate attosecond beamline for time-resolved XUV-IR coincidence spectroscopy
Ultrastable, high-repetition-rate attosecond beamline for time-resolved XUV-IR coincidence spectroscopy Open
The implementation of attosecond photoelectron-photoion coincidence spectroscopy for the investigation of atomic and molecular dynamics calls for a high-repetition-rate driving source combined with experimental setups characterized by exce…
View article: Differential Measurement of Electron Ejection after Two-Photon Two-Electron Excitation of Helium
Differential Measurement of Electron Ejection after Two-Photon Two-Electron Excitation of Helium Open
We report the measurement of the photoelectron angular distribution of two-photon single-ionization near the 2p^{2} ^{1}D^{e} double-excitation resonance in helium, benchmarking the fundamental nonlinear interaction of two photons with two…
View article: High-repetition rate attosecond beamline for multi-particle coincidence experiments
High-repetition rate attosecond beamline for multi-particle coincidence experiments Open
In this paper, a 3-dimensional photoelectron/ion momentum spectrometer (reaction microscope) combined with a table-top attosecond beamline based on a high-repetition rate (49 kHz) laser source is presented. The beamline is designed to achi…
View article: Inner-Shell-Ionization-Induced Femtosecond Structural Dynamics of Water Molecules Imaged at an X-Ray Free-Electron Laser
Inner-Shell-Ionization-Induced Femtosecond Structural Dynamics of Water Molecules Imaged at an X-Ray Free-Electron Laser Open
The ultrafast structural dynamics of water following inner-shell ionization is a crucial issue in high-energy radiation chemistry. We have exposed isolated water molecules to a short X-ray pulse from a free-electron laser and detected mome…
View article: Synchronized beamline at FLASH2 based on high-order harmonic generation for two-color dynamics studies
Synchronized beamline at FLASH2 based on high-order harmonic generation for two-color dynamics studies Open
We present the design, integration, and operation of the novel vacuum ultraviolet (VUV) beamline installed at the free-electron laser (FEL) FLASH. The VUV source is based on high-order harmonic generation (HHG) in gas and is driven by an o…
View article: TrapREMI: A reaction microscope inside an electrostatic ion beam trap
TrapREMI: A reaction microscope inside an electrostatic ion beam trap Open
A new experimental setup has been developed to investigate the reactions of molecular ions and charged clusters with a variety of projectile beams. An Electrostatic Ion Beam Trap (EIBT) stores fast ions at keV energies in an oscillatory mo…
View article: Sub-femtosecond optical control of entangled states
Sub-femtosecond optical control of entangled states Open
For photo-dissociation of a single hydrogen molecule (H2) with combined XUV and IR laser pulses, we demonstrate optical control of the emission direction of the photoelectron with respect to the outgoing neutral fragment (the H-atom). Depe…
View article: Linear dichroism in few-photon ionization of laser-dressed helium
Linear dichroism in few-photon ionization of laser-dressed helium Open
Ionization of laser-dressed atomic helium is investigated with focus on photoelectron angular distributions stemming from two-color multi-photon excited states. The experiment combines extreme ultraviolet (XUV) with infrared (IR) radiation…
View article: Publisher's Note: “Laser-induced electron diffraction of the ultrafast umbrella motion in ammonia” [Struct. Dyn. <b>8</b>, 014301 (2021)]
Publisher's Note: “Laser-induced electron diffraction of the ultrafast umbrella motion in ammonia” [Struct. Dyn. <b>8</b>, 014301 (2021)] Open
[This corrects the article DOI: 10.1063/4.0000046.].