A5069389476- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Physics Studies
- Particle accelerators and beam dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Laser-induced spectroscopy and plasma
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear physics research studies
- Ion-surface interactions and analysis
- Astrophysics and Star Formation Studies
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Photocathodes and Microchannel Plates
- Molecular Spectroscopy and Structure
- Laser-Matter Interactions and Applications
- Spectroscopy and Laser Applications
- Plasma Diagnostics and Applications
- Atmospheric Ozone and Climate
- Quantum, superfluid, helium dynamics
- Advanced Frequency and Time Standards
- Nuclear Physics and Applications
- Electron and X-Ray Spectroscopy Techniques
- Muon and positron interactions and applications
- Astro and Planetary Science
- Laser-Plasma Interactions and Diagnostics
Max Planck Institute for Nuclear Physics
2015-2025
Fraunhofer Institute for Solar Energy Systems
2012-2025
Amgen (Germany)
2023
Saint Francis Medical Center
2022
Jersey Shore University Medical Center
2022
Continental (Germany)
2016
Weizmann Institute of Science
1996-2016
Columbia University
2015-2016
Max Planck Society
2006-2015
Heidelberg University
1995-2015
In chemistry and biology, chirality, or handedness, refers to molecules that exist in two spatial configurations are incongruent mirror images of one another. Almost all biologically active chiral, the correct determination their absolute configuration is essential for understanding development processes involving chiral molecules. Anomalous x-ray diffraction vibrational optical activity measurements broadly used determine solid liquid samples. Determining gas phase still a formidable...
The first successful laser cooling of ions at relativistic energies was observed the Heidelberg TSR storage ring. A $^{7}\mathrm{Li}^{+}$-ion beam 13.3 MeV oberlapped with resonant copropagating and counterpropagating beams. metastable were cooled from 260 K to a longitudinal temperature below 3 decelerated by several keV. velocity distribution determined fluorescence method. After strongly enhanced narrow peak appeared in Schottky noise spectrum addition uncooled ion distribution.
Energies and absolute cross sections for dielectronic recombination of lithiumlike ${\mathrm{Cu}}^{26+}$ via \ensuremath{\Delta}N=0 \ensuremath{\Delta}N=1 resonances have been measured at the Heidelberg heavy-ion storage ring TSR employing electron cooler as a target free electrons. In particular, associated with 2s\ensuremath{\rightarrow}2p 2s\ensuremath{\rightarrow}3l excitations observed. Resonances due to doubly excited states 1${\mathit{s}}^{2}$2${\mathit{p}}_{1/2}$nl...
An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR Heidelberg. The Doppler-shifted frequencies a two-level transition 7Li+ v=0.064c have measured forward and backward direction to an accuracy Deltanu/nu=1 x 10(-9) collinear saturation spectroscopy. result confirms relativistic Doppler formula sets new limit 2.2 10(-7) for deviations from factor gamma(SR)=(1-v2/c2)(-1/2).
State-resolved cross sections for the dielectronic recombination of hydrogenlike oxygen ions with free electrons have been measured first time using electron cooling device in heavy-ion Test Storage Ring Heidelberg. Energies and individual terms configuration 2l2l' were determined. Two-electron resonances 2lnl' n\ensuremath{\ge}3 contribute 90% to total dielectronic-recombination section. are reasonable agreement available calculations.
We describe a system combining an ion beam trap and low energy electron target in which the interaction between electrons vibrationally cold molecular ions clusters can be studied. The entire uses only electrostatic fields for both trapping focusing, thus being able to store particles without mass limit. Preliminary results impact neutralization of C2− aluminum are presented.
Isotope shifts in dielectronic recombination spectra were studied for Li-like (A)Nd(57+) ions with A=142 and A=150. From the displacement of resonance positions energy deltaE(142 150)(2s-2p(1/2))=40.2(3)(6) meV [(stat)(sys)] 150)(2s-2p(3/2))=42.3(12)(20) 2s-2p(j) transitions deduced. An evaluation these values within a full QED treatment yields change mean-square charge radius (142 150)deltar(2)=-1.36(1)(3) fm(2). The approach is conceptually new combines advantage simple atomic structure...
First-principles computations and experimental measurements of transition energies are carried out for vibrational overtone lines the triatomic hydrogen ion H(3)(+) corresponding to floppy vibrations high above barrier linearity. Action spectroscopy is improved detect extremely weak visible-light spectral on cold trapped ions. A highly accurate potential surface obtained from variational calculations using explicitly correlated Gaussian wave function expansions. After nonadiabatic...
An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, put into operation. With a circumference 35 m, the ion-beam vacuum chambers all beam optics are in cryostat cooled by closed-cycle liquid helium system. At temperatures as low (5.5 ± 1) K inside time constants several minutes almost an hour were observed atomic molecular, anion cation at 60 keV. The intensity, energy-dependent...
We present the concluding result from an Ives-Stilwell-type time dilation experiment using Li+7 ions confined at a velocity of β=v/c=0.338 in storage ring ESR Darmstadt. A Λ-type three-level system within hyperfine structure Li+7S13→P23 line is driven by two laser beams aligned parallel and antiparallel relative to ion beam. The lasers' Doppler shifted frequencies required for resonance are measured with accuracy <4×10−9 optical-optical double spectroscopy. This allows us verify special...
We demonstrate that the dissociative recombination of ${\mathrm{D}}_{2}{\mathrm{H}}^{+}$ with low-energy electrons depends on rotational energy molecular ion such highly excited ions have a larger rate coefficient than colder ones. Observations an beam continuously interacting at low relative velocity indicate levels are preferentially depleted which, in competition radiative heating due to blackbody radiation, provides opportunity for controlling temperature stored molecules.
We have measured the dielectronic recombination cross section of ${\mathrm{Se}}^{25+}$ ions at center-of-mass energies from 1 to 1800 eV using merged electron and ion beams in Heidelberg heavy-ion Test Storage Ring (TSR). All resonances involving changes \ensuremath{\Delta}N=0 \ensuremath{\Delta}N=1 core principal quantum number N are covered with high-energy resolution (ranging 0.6 90 \ensuremath{\approxeq}6 1600 eV). A strong contribution Rydberg 1200--1700 is observed. The results...
The cross section as well the branching ratios for dissociative recombination of ground-state ${\mathrm{CH}}^{+}$ ions with electrons have been measured using heavy-ion storage-ring technique and two-dimensional fragment imaging. Although absolute value at thermal energies is found to be in very good agreement theory, several unpredicted narrow resonances are also present data. These structures interpreted due an indirect process via core-excited Rydberg states. branching-ratio measurement...
The first observation of laser-induced recombination, performed with merged beams protons, electrons, and laser photons in an ion storage ring, is reported. process was used to study the photorecombination spectrum high resolution. Deviations from earlier theoretical predictions turned out be due a weak external electric field could well described by simple extension field-free quantum-mechanical theory, based on properties classical electron trajectories combined Coulomb fields.
The energy-resolved rate coefficient for the dissociative recombination (DR) of $\mathrm{H}_{3}{}^{+}$ with slow electrons has been measured by storage-ring method using an ion beam produced from a radiofrequency multipole trap, employing buffer-gas cooling at 13 K. electron energy spread merged-beams measurement is reduced to $500\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$ cryogenic GaAs photocathode. This and previous cold-$\mathrm{H}_{3}{}^{+}$ jointly confirm capability storage rings,...
The electric dipole intercombination decay of the $2s2p$ $^{3}P_{1}^{0}$ level in Be-like ion ${\mathrm{C}}^{2+}$ has been optically observed with ions circulating a heavy-ion storage ring. measured transition probability $(102.94\ifmmode\pm\else\textpm\fi{}0.14)\phantom{\rule{0ex}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$, corresponding to lifetime $(9.714\ifmmode\pm\else\textpm\fi{}0.013)$ ms, is good agreement recent theoretical calculations. This precision measurement thus resolves...
The low-energy C IV dielectronic recombination (DR) rate coefficient associated with 2s → 2p Δn = 0 excitations of this lithium-like ion has been measured high-energy resolution at the heavy-ion storage ring TSR Max-Planck-Institut für Kernphysik in Heidelberg, Germany. experimental procedure and especially detection probabilities for high Rydberg states produced by are discussed detail. From data a Maxwellian plasma is derived ±15% systematic uncertainty parameterized ready use...
The radiative decay rate of ${\mathrm{C}}^{4+}$ ions in the metastable 1s2${\mathit{s}}^{3}$${\mathit{S}}_{1}$ state has been measured at ion storage ring TSR Heidelberg, observing time dependence dielectronic recombination on resonances characteristic for this state. very accurate result 48.57\ifmmode\pm\else\textpm\fi{}0.11 ${\mathit{s}}^{\mathrm{\ensuremath{-}}1}$ allows us to distinguish between different theoretical approaches. Our is excellent agreement with a calculation...
Term energies for dielectronic-recombination Rydberg resonances below 0.07 eV are determined Sc18+ with absolute accuracies 0.0002 by electron collision spectroscopy in an ion storage ring, using the twin-electron-beam technique and a cryogenic photocathode. The lithiumlike 2s_{1/2}-2p_{3/2} transition energy Z=21 is to 4.6 ppm, less than 1% of few-body effects on radiative corrections. Features from hyperfine structure 2s state could be resolved spectrum.
Dielectronic recombination (DR) of xenonlike ${\mathrm{W}}^{20+}$ forming ${\mathrm{W}}^{19+}$ has been studied experimentally at a heavy-ion storage ring. A merged-beams method employed for obtaining absolute rate coefficients electron-ion in the collision-energy range 0--140 eV. The measured coefficient is dominated by strong DR resonances even lowest experimental energies. At plasma temperatures where fractional abundance expected to peak fusion plasma, derived over factor 4 larger than...