Publications (38)
Fourfold Differential Photoelectron Circular Dichroism
K. Fehre, N. M. Novikovskiy, S. Grundmann +28
We report on a joint experimental and theoretical study of photoelectron circular dichroism (PECD) in methyloxirane. By detecting O 1s-photoelectrons in coincidence with fragment i…
A new route for enantio-sensitive structure determination by photoelectron scattering on molecules in the gas phase
K. Fehre, N. M. Novikovskiy, S. Grundmann +28
X-ray as well as electron diffraction are powerful tools for structure determination of molecules. Studies on randomly oriented molecules in the gas-phase address cases in which mo…
Photon-momentum-induced molecular dynamics in photoionization of N at keV
M. Kircher, J. Rist, F. Trinter +16
We investigate K-shell ionization of N at 40 keV photon energy. Using a COLTRIMS reaction microscope we determine the vector momenta of the photoelectron, the Auger electron an…
à ngstrom depth resolution with chemical specificity at the liquid-vapor interface
R. Dupuy, J. Filser, C. Richter +13
The determination of depth profiles across interfaces is of primary importance in many scientific and technological areas. Photoemission spectroscopy is in principle well suited fo…
Double--hole resonances in single photoionization of He-like B ions
A. Müller, P. -M. Hillenbrand, S. -X. Wang +8
Within a joint experimental and theoretical research project, single photoionization of He-like B ions was investigated in the energy range from approximately 250 to 1200~eV…
Imaging the square of the correlated two-electron wave function of a hydrogen molecule
M. Waitz, R. Y. Bello, D. Metz +21
The toolbox for imaging molecules is well-equipped today. Some techniques visualize the geometrical structure, others the electron density or electron orbitals. Molecules are many-…
Revealing the Two-Electron Cusp in the Ground States of He and H2 via Quasifree Double Photoionization
S. Grundmann, V. Serov, F. Trinter +15
We report on kinematically complete measurements and ab initio non-perturbative calculations of double ionization of He and H2 by a single 800 eV circularly polarized photon. We co…
Separating Dipole and Quadrupole Contributions to Single-Photon Double Ionization
S. Grundmann, F. Trinter, A. W. Bray +12
We report on a kinematically complete measurement of double ionization of helium by a single 1100 eV circularly polarized photon. By exploiting dipole selection rules in the two-el…
Closed-loop recycling of rare liquid samples for gas-phase experiments
K. Fehre, M. Pitzer, F. Trinter +4
Many samples of current interest in molecular physics and physical chemistry exist in the liquid phase and are vaporized for the use in gas cells, diffuse gas targets or molecular…
Interatomic-Coulombic-decay-induced recapture of photoelectrons in helium dimers
P. Burzynski, F. Trinter, J. B. Williams +17
We investigate the onset of photoionization shakeup induced interatomic Coulombic decay (ICD) in He2 at the He+*(n = 2) threshold by detecting two He+ ions in coincidence. We find…
Vibrationally Resolved Inner-Shell Photoexcitation of the Molecular Anion C
S. Schippers, P. -M. Hillenbrand, A. Perry-Sassmannshausen +6
Carbon core-hole excitation of the molecular anion C has been experimentally studied at high resolution by employing the photon-ion merged-beams technique at a synchrotr…
Photoelectron circular dichroism of O 1-photoelectrons of uniaxially oriented trifluoromethyloxirane: Energy dependence and sensitivity to molecular configuration
G. Nalin, K. Fehre, F. Trinter +25
The photoelectron circular dichroism (PECD) of the O 1s-photoelectrons of trifluoromethyloxirane(TFMOx) is studied experimentally and theoretically for different photoelectron kine…
Role of the Coulomb Potential in Compton Scattering
N. Melzer, M. Kircher, A. Pier +18
We report a fully differential study of ionization of the Ne L-shell by Compton scattering of 20 keV photons. We find two physical mechanisms which modify the Compton-electron emis…
Recovery of high-energy photoelectron circular dichroism through Fano interference
G. Hartmann, M. Ilchen, Ph. Schmidt +10
It is commonly accepted that the magnitude of a photoelectron circular dichroism (PECD) is governed by the ability of an outgoing photoelectron wave packet to probe the chiral asym…
Breakdown of the spectator concept in low-electron-energy resonant decay processes
A. Mhamdi, J. Rist, D. Aslitürk +16
We suggest that low energy electrons, released by resonant decay processes, experience substantial scattering on the electron density of excited electrons, which remain a spectator…
The role of spin and angular momentum in strong-field ionization
D. Trabert, A. Hartung, S. Eckart +7
The spin polarization of electrons from multiphoton ionization of Xe by 395 nm circularly polarized laser pulses at W/cm has been measured. At this photon energ…
Vibrationally Resolved Decay Width of Interatomic Coulombic Decay in HeNe
F. Trinter, J. B. Williams, M. Weller +17
We investigate the ionization of HeNe from below the He 1s3p excitation to the He ionization threshold. We observe HeNe ions with an enhancement by more than a factor of 60 whe…
Direct observation of interatomic Coulombic decay and subsequent ion-atom scattering in helium nanodroplets
F. Wiegandt, F. Trinter, K. Henrichs +13
We report on the experimental observation of interatomic Coulombic decay (ICD) in pure He nanoclusters of mean sizes between 5000 and 30000 and the subsequent scatt…
Determination of the He-He, Ne-Ne, Ar-Ar, and H interaction potential by wave function imaging
S. Zeller, M. Kunitski, J. Voigtsberger +10
We report on a direct method to measure the internuclear potential energy curve of diatomic systems. A COLTRIMS reaction microscope was used to measure the squares of the vibration…
Search for isotope effects in projectile and target ionization in swift He on H or D collisions
F. Trinter, M. Waitz, M. S. Schöffler +7
Using the cold target recoil ion momentum spectroscopy (COLTRIMS) technique, we have measured the simultaneous projectile and target ionization in collisions of He projectiles…
Multiple Photodetachment of Oxygen Anions via K-Shell Excitation and Ionization: Direct Double-Detachment Processes and Subsequent Deexcitation Cascades
S. Schippers, A. Hamann, A. Perry-Sassmannshausen +6
Experimental cross sections for m-fold photodetachment (m=2-5) of oxygen anions via K-shell excitation and ionization were measured in the photon-energy range of 525-1500 eV using…
Ion and Electron Momentum Distributions from Single and Double Ionization of Helium Induced by Compton Scattering
M. Kircher, F. Trinter, S. Grundmann +18
We present the momentum distributions of the nucleus and of the electrons from double ionization of the helium atom by Compton scattering of photons with keV. We find that…
Agreement at last: an experimental and theoretical study on the single ionization of helium by fast proton impact
H. Gassert, O. Chuluunbaatar, M. Waitz +20
Even though ion/atom-collision is a mature field of atomic physics great discrepancies between experiment and theoretical calculations are still common. Here we present experimenta…
Ejection of quasi-free electron pairs from the helium atom ground state by single photon absorption
M. S. Schöffler, C. Stuck, M. Waitz +14
We investigate single photon double ionization (PDI) of helium at photon energies of 440 and 800 eV. We observe doubly charged ions with close to zero momentum corresponding to ele…
Frustrated Coulomb explosion of small helium clusters
S. Kazandjian, J. Rist, M. Weller +17
Almost ten years ago, energetic neutral hydrogen atoms were detected after a strong-field double ionization of H. This process, called 'frustrated tunneling ionization', occurs…
Multiple photodetachment of carbon anions via single and double core-hole creation
A. Perry-Sassmannshausen, T. Buhr, A. Borovik +8
We report on new measurements of m-fold photodetachment (m=2-5) of carbon anions via K-shell excitation and ionization. The experiments were carried out employing the photon-ion me…
Absolute ion detection efficiencies of microchannel plates and funnel microchannel plates for multi-coincidence detection
K. Fehre, D. Trojanowskaja, J. Gatzke +11
Modern momentum imaging techniques allow for the investigation of complex molecules in the gas phase by detection of several fragment ions in coincidence. For these studies, it is…
Recoil-Induced Asymmetry of Nondipole Molecular Frame Photoelectron Angular Distributions in the Hard X-ray Regime
M. Kircher, J. Rist, F. Trinter +15
We investigate angular emission distributions of the 1s-photoelectrons of N ionized by linearly polarized synchrotron radiation at keV. As expected, nondipole contrib…
Experimental Observation of Non-Exponential Auger-Meitner Decay of Inner-Shell-Excited CO
M. Weller, G. Kastirke, J. Rist +10
Electronically excited atoms or molecules may deexcite by emission of a secondary electron through an Auger-Meitner decay. This deexcitation process is typically considered to be e…
Sideband Modulation by Sub-Cycle Interference
S. Eckart, D. Trabert, K. Fehre +9
We experimentally and theoretically show that the electron energy spectra strongly depend on the relative helicity in highly intense, circularly polarized two-color laser fields wh…
Ion impact induced Interatomic Coulombic Decay in neon and argon dimers
H. -K. Kim, H. Gassert, M. S. Schöffler +16
We investigate the contribution of Interatomic Coulombic Decay induced by ion impact in neon and argon dimers (Ne and Ar) to the production of low energy electrons. Our exp…
Double to tenfold M-shell photoionization of singly charged lanthanum ions
M. Looshorn, B. M. Döhring, P. -M. Hillenbrand +9
Using the photon-ion merged-beams technique at the PETRA\,III synchrotron light source, we have measured cross sections for double and up to tenfold photoionization of La ion…
Electron localization in dissociating by retroaction of a photoelectron onto its source
M. Waitz, D. Aslitürk, N. Wechselberger +19
We investigate the dissociation of into a proton and a after single ionization with photons of an energy close to the threshold. We find that the and the …
Probing Instantaneous Single-Molecule Chirality in the Planar Ground State of Formic Acid
D. Tsitsonis, M. Kircher, N. M. Novikovskiy +12
We experimentally demonstrate that individual molecules of formic acid are chiral even when they are in the vibronic ground state, which has a planar equilibrium structure. We ioni…
Imaging the He quantum halo state using a free electron laser
S. Zeller, M. Kunitski, J. Voigtsberger +24
We report on coulomb explosion imaging of the wavefunction of the quantum halo system He. Each atom of this system is ionized by tunnelionization in a femto second laser pulse…
Selective Bond Breaking in CO Induced by Photoelectron Recoil
J. Weiherer, N. Melzer, M. Kircher +16
After core-ionization of CO, typically an Auger-Meitner decay takes place, leading to the formation of a dicationic molecule that may dissociate into CO and O. We demon…
Multiple photodetachment of silicon anions via K-shell excitation and ionization
A. Perry-Sassmannshausen, T. Buhr, M. Martins +5
Experimental cross sections for -fold photodetachment () of silicon anions via -shell excitation and ionization were measured in the photon-energy range of 1830-1900 e…
A measurement of the evolution of Interatomic Coulombic Decay in the time domain
F. Trinter, J. B. Williams, M. Weller +17
During the last 15 years a novel decay mechanism of excited atoms has been discovered and investigated. This so called ''Interatomic Coulombic Decay'' (ICD) involves the chemical e…