Related papers: Fine- and hyperfine-structure effects in molecular…
We develop a model for predicting fine- and hyperfine intensities in the direct photoionization of molecules based on the separability of electron and nuclear spin states from vibrational-electronic states. Using spherical tensor algebra,…
Here, we report on the nonlinear ionization of argon atoms in the short wavelength regime using ultraintense x rays from the European XFEL. After sequential multiphoton ionization, high charge states are obtained. For photon energies that…
Trapping cold, chemically important molecules with electromagnetic fields is a useful technique to study small molecules and their interactions. Traps provide long interaction times that are needed to precisely examine these low density…
We report on the production of cold, state-selected H$_2^+$ molecular ions in a linear RF trap. The ions are produced by (3+1) resonance-enhanced multi-photon ionisation (REMPI) of H$_2$, and sympathetically cooled by laser-cooled Be$^+$…
Hyperfine-structures of highly charged ions (HCIs) are favourable spectroscopic targets for exploring fundamental physics as well as nuclear properties. Recent proposals of HCI atomic clocks highlight their importance, especially for…
The ability to prepare molecular ions in selected quantum states enables studies in areas such as chemistry, metrology, spectroscopy, quantum information, and precision measurements. Here, we demonstrate $(2+1)$ resonance-enhanced…
The linear polarization of the characteristic photon emission from few-electron ions is studied for its sensitivity with regard to the nuclear spin and magnetic moment of the ions. Special attention is paid, in particular, to the…
We report on efficient rovibrational state-selective loading of single H$_2^+$ molecular ions into a cryogenic linear Paul trap using (2+1) resonance-enhanced multi-photon ionization (REMPI). The H$_2^+$ ions are created by resonant…
Ultraintense pulses from X-ray free-electron lasers can drive, within femtoseconds, multiple processes in the inner shells of atoms and molecules in all phases of matter. The ensuing complex ionization pathways of outer-shell electrons from…
Magnetic Particle Imaging (MPI) is a recent imaging modality where superparamagnetic nanoparticles are employed as tracers. The reconstruction task is to obtain the spatial particle distribution from a voltage signal induced by the…
In molecular beam scattering experiments, an important technique for measuring product energy and angular distributions is velocity map imaging following photoionization. For studies with cold molecular beams, the resolution is often…
For crucial tests between theory and experiment, ab initio close coupling calculations are carried out for photoionization of O II, O III, O IV, O V. The relativistic fine structure and resonance effects are studied using the R-matrix and…
Photoelectron circular dichroism (PECD) is a highly sensitive enantiospecific spectroscopy for studying chiral molecules in the gas phase using either single-photon ionization or multiphoton ionization. In the short pulse limit investigated…
We present a multichannel photoelectron interferometry technique based on trichromatic pulse shaping for unambiguous determination of quantum phases in multiphoton ionization (MPI) of potassium atoms. The colors of the laser field are…
We present the integrated imaging of cold molecules in a microchip environment. The on-chip de- tection is based on REMPI, which is quantum-state-selective and generally applicable. We demon- strate and characterize time-resolved spatial…
We investigate the effect of resonances in photoionization and recombination cross sections computed using the R-matrix method. Photoionization and recombination rates derived from high-resolution cross sections for oxygen ions are compared…
We outline a formalism and develop a computational procedure to treat the process of multiphoton ionization (MPI) of atomic targets in strong laser fields. We treat the MPI process nonperturbatively as a decay phenomenon by solving a…
Photoionization of an atom via interatomic correlations to N neighboring atoms may be strongly enhanced due to constructive interference of quantum pathways. The ionization proceeds via resonant photoexcitation of a neighbor atom and…
Recent experimental work on the photorecombination and the photoionization of astrophysically relevant atomic ions employing the merged-beams technique at heavy-ion storage-rings and synchrotron-light sources, respectively, is summarized.…
Magnetic particle imaging (MPI) is an imaging modality exploiting the nonlinear magnetization behavior of (super-)paramagnetic nanoparticles to obtain a space- and often also time-dependent concentration of a tracer consisting of these…