A5071897609- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Particle accelerators and beam dynamics
- Advanced Chemical Physics Studies
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Ion-surface interactions and analysis
- Particle Detector Development and Performance
- Cold Atom Physics and Bose-Einstein Condensates
- Spectroscopy and Laser Applications
- Spectroscopy and Quantum Chemical Studies
- Atmospheric Ozone and Climate
- Magnetic confinement fusion research
- Analytical Chemistry and Chromatography
- Superconducting Materials and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Diamond and Carbon-based Materials Research
- Atomic and Subatomic Physics Research
- Scientific Research and Discoveries
- Muon and positron interactions and applications
- Nuclear Physics and Applications
- Molecular Spectroscopy and Structure
- Coordination Chemistry and Organometallics
- Advanced Frequency and Time Standards
- Fullerene Chemistry and Applications
Stockholm University
2015-2025
Stockholm Environment Institute
2024
AlbaNova
2012-2023
Lund University
2013
University of Gothenburg
2013
European Spallation Source
2013
Helse Førde
2009
The branching ratios of the different reaction pathways and overall rate coefficients dissociative recombination reactions CH3OH2+ CD3OD2+ have been measured at CRYRING storage ring located in Stockholm, Sweden. Analysis data yielded result that formation methanol or deuterated accounted for only 3 6% total CD3OD2+, respectively. Dissociative both isotopomeres mainly involves fragmentation C-O bond, major process being three-body break-up forming CH3, OH H (CD3, OD D). cross sections are...
Mutual neutralization of hydronium (H
We report on the first storage of ion beams in Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. have produced atomic carbon anions and small anion molecules (\documentclass[12pt]{minimal}\begin{document}${\rm C}_n^-$\end{document}Cn−, n = 1, 2, 3, 4) a sputter source. The were accelerated to 10 keV kinetic energy stored an electrostatic ring enclosed vacuum chamber 13 K. For \documentclass[12pt]{minimal}\begin{document}${\rm C}_2^-$\end{document}C2− molecular we...
Abstract Negative ions are important in many areas of science and technology, e.g., interstellar chemistry, for accelerator-based radionuclide dating, anti-matter research. They unique quantum systems where electron-correlation effects govern their properties. Atomic anions loosely bound systems, which with very few exceptions lack optically allowed transitions. This limits prospects high-resolution spectroscopy, related negative-ion detection methods. Here, we present a method to measure...
<title>Abstract</title> We have studied the MN of NO<sup>+</sup> with NO<sub>2</sub><sup>-</sup> under single-collision conditions at a collision energy ≈0.1 eV. Combining cryogenically stored-and-merged ion beams coincident-product imaging, we determine that reaction predominantly produces ground-state NO and electronically excited NO<sub>2</sub>, fraction which rapidly dissociates to + O. As consequence, prior studies, based on fluorescence detection, missed more than 97% products. New...
We apply near-threshold laser photodetachment to characterize the rotational quantum level distribution of OH^{-} ions stored in cryogenic ion-beam storage ring DESIREE at Stockholm University. find that relax a temperature 13.4±0.2 K with 94.9±0.3% ground state. This is consistent 13.5±0.5 as measured eight silicon diodes but contrast all earlier studies traps and rings where temperatures were always much higher than those devices their lowest temperatures. Furthermore, we actively modify...
Abstract Laboratory studies play a crucial role in understanding the chemical nature of interstellar medium (ISM), but disconnect between experimental timescales and reactions space can make direct comparison observations, laboratory, model results difficult. Here we study survival reactive fragments polycyclic aromatic hydrocarbon (PAH) coronene, where individual C atoms have been knocked out molecules hard collisions with He at stellar wind supernova shockwave velocities. Ionic are stored...
We report the first observation of Young-type interference effects in a two-electron transfer process. These change strongly as projectile velocity changes fast (1.2 and 2.0 MeV) He(2+) + H(2) collisions manifested strong variations double-electron capture rates with orientation. This is consistent fully quantum mechanical calculations, which ignore sequential electron transfer, simple de Broglie wave picture assuming that probabilities are higher where passes close to either one nuclei.
<i>Aims. <i/>Determination of branching fractions, cross sections and thermal rate coefficients for the dissociative recombination CD<sub>3<sub/>OCD<sub>2<sub/><sup>+<sup/> (0–0.3 eV) (CD<sub>3<sub/>)<sub>2<sub/>OD<sup>+<sup/> (0–0.2 at low relative kinetic energies encountered in interstellar medium.<i>Methods. <i/>The measurements were carried out using merged electron ion beams CRYRING storage ring, Stockholm, Sweden.<i>Results. <i/>For we have experimentally determined fraction ejection...
We report experimental angular differential cross sections for nonradiative single-electron capture in $p$-He collisions ($p+$ He $\ensuremath{\rightarrow}$ H $+$ He${}^{+}$) with a separate peak at the $0.47$ mrad Thomas scattering angle energies $1.3--12.5$ MeV range. find that intensity of this scales projectile velocity as ${v}_{\mathrm{P}}^{\ensuremath{-}11}$. This constitutes first test prediction from 1927 by L. H. [Proc. R. Soc. 114, 561 (1927)]. At our highest energy, contributes...
We have studied the mutual neutralization reaction of vibronically cold <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msup><a:mrow><a:mi>NO</a:mi></a:mrow><a:mrow><a:mo>+</a:mo></a:mrow></a:msup></a:mrow></a:math> with <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:msup><c:mrow><c:mi mathvariant="normal">O</c:mi></c:mrow><c:mrow><c:mo>−</c:mo></c:mrow></c:msup></c:mrow></c:math> at a collision energy <f:math...
We have developed an experimental technique to study charge- and energy-flow processes in sub-eV collisions between oppositely charged, internally cold, ions of atoms, molecules, clusters. Two ion beams are stored separate rings the cryogenic ion-beam storage facility DESIREE, merged a common straight section where set biased drift tubes is used control center-of-mass collision energy locally fine steps. Here, we present measurements on mutual neutralization ${\mathrm{Li}}^{+}$...
Branching ratios and absolute cross sections have been measured for the dissociative recombination of DCCCN+ DCCCND+ using CRYRING ion storage ring. In case dissociation yielding D + C3N those leading to two fragments containing a pair heavy atoms dominate, whereas pathways producing fragment with three play only minor role. Conversely, DCCCND+, channels preserving carbon chain or each are detected. The reactions very similar can be fitted expressions σ = × 10-15E(eV)-1.05±0.02 cm2...
We present experimental evidence for a strong dependence on the angle between molecular axis of ${\mathrm{H}}_{2}$ and direction incoming projectile $(p)$ in cross section transfer excitation fast $p\text{\ensuremath{-}}{\mathrm{H}}_{2}$ collisions. For collision energies 1.0 $1.3\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$ we find good agreement observed data an analytical expression based two-atomic-center description using Brinkman-Kramers amplitudes. This clearly shows that angular is result...
Abstract A novel cryogenic electrostatic storage device consisting of two ion-beam rings with a common straight section for studies interactions between oppositely charged ions at low and well-defined relative velocities is under construction Stockholm University. Here we consider the prospect using this new tool to measure cross-sections rate coefficients mutual neutralization reactions importance in interstellar ion chemistry general specifically cosmic pre-biotic chemistry.
The present paper reports on a merged-beam experiment mutual neutralization between ${\mathrm{Na}}^{+}$ and ${\mathrm{D}}^{\ensuremath{-}}$. For this experiment, we have used the DESIREE ion-beams storage-ring facility. reaction products are detected using position- time-sensitive detector, which ideally allows for determination of population each individual quantum state in final atomic systems. Here, $4s, 3d$, $4p$ states Na observed all cases D atom is its ground $1s ^{2}S$. respective...
We present experimental final-state distributions for Mg atoms formed in Mg^{+}+D^{-} mutual neutralization reactions at center-of-mass collision energies of 59±12 meV by using the merged-beams method. Comparisons with available full-quantum results reveal large discrepancies and a previously underestimated total rate coefficient up to factor 2 0-1 eV (<10^{4} K) regime. Asymptotic model calculations are shown describe process much better we recommend applying this method more complex iron...
Some years ago it was found at GSI in Darmstadt that the momentum spread of electron-cooled beams highly charged ions dropped abruptly to very low values when particle number decreased 10 000 or less. This has been interpreted as an ordering ions, such they line up after one another ring. We report observations similar transitions CRYRING, including accompanying drop Schottky-noise power. also introduce a model ordered beam from which power can be calculated numerically. The good agreement...
Aims. We determine branching fractions, cross sections and thermal rate constants for the dissociative recombination of CD3CDOD+ CH3CH2OH at low relative kinetic energies encountered in interstellar medium.
The intrinsic radiative lifetimes of the $5d^{10}6s$ $^{2}\text{S}_{1/2}$ and $5d^{9}6s^{2}$ $^{2}\text{D}_{3/2}$ bound excited states in platinum anion $\text{Pt}^{-}$ have been studied at cryogenic temperatures Double ElectroStatic Ion Ring Experiment (DESIREE) facility Stockholm University. lifetime higher-lying state was measurement to be 2.54$\pm$0.10 s, while only a range 50 - 200 ms could estimated for fine-structure level. storage ion beam measured little over 15 minutes ring...
The former storage ring CRYRING has been shipped from the Manne Siegbahn Laboratory in Stockholm to Darmstadt as a Swedish in-kind contribution FAIR. At its new location downstream of ESR all ion species presently accessible can be transferred CRYRING, which ions with rigidities between 1.44 and 0.054 Tm stored. original layout modified by reconfiguring sequence straight sections slightly increasing circumference ESR/2. Ions injected or an independent 300 keV/u RFQ test injector....