A5063013135- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Physics Studies
- Astrophysics and Star Formation Studies
- Fullerene Chemistry and Applications
- Ion-surface interactions and analysis
- Diamond and Carbon-based Materials Research
- Cold Atom Physics and Bose-Einstein Condensates
- Graphene research and applications
- Atmospheric Ozone and Climate
- Spectroscopy and Quantum Chemical Studies
- Carbon Nanotubes in Composites
- Quantum, superfluid, helium dynamics
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Analytical Chemistry and Chromatography
- Advanced Combustion Engine Technologies
- Advanced Proteomics Techniques and Applications
- Photochemistry and Electron Transfer Studies
- Polymer Nanocomposite Synthesis and Irradiation
- Stellar, planetary, and galactic studies
- Spectroscopy and Laser Applications
- Advanced Physical and Chemical Molecular Interactions
- Nuclear physics research studies
- Particle accelerators and beam dynamics
Stockholm University
2016-2025
Stockholm Environment Institute
2014-2024
RIKEN
2024
Pioneer (Japan)
2024
AlbaNova
2013-2023
Florence (Netherlands)
2019
University of Gothenburg
2013
European Spallation Source
2013
Lund University
2013
University of Washington
2009-2010
We describe the design of a novel type storage device currently under construction at Stockholm University, Sweden, using purely electrostatic focussing and deflection elements, in which ion beams opposite charges are confined extreme high vacuum cryogenic conditions separate "rings" merged over common straight section. The this double ring experiment uniquely allows for studies interactions between cations anions low well-defined internal temperatures centre-of-mass collision energies down...
Abstract After decades of searching, astronomers have recently identified specific Polycyclic Aromatic Hydrocarbons (PAHs) in space. Remarkably, the observed abundance cyanonaphthalene (CNN, C 10 H 7 CN) Taurus Molecular Cloud (TMC-1) is six orders magnitude higher than expected from astrophysical modeling. Here, we report unimolecular dissociation and radiative cooling rate coefficients 1-CNN isomer its cationic form. These results are based on measurements time-dependent neutral product...
Mutual neutralization of hydronium (H
We have performed density functional theory calculations for a range of neutral, singly, and multiply charged polycyclic aromatic hydrocarbons (PAHs), their fragmentation products H-, H$^+$+-, C$_2$2H$_2$2-, C$_2$2H$_2^+$2+-emissions. The adiabatic vertical ionization energies follow linear dependencies as functions charge state all five intact PAHs (naphthalene, biphenylene, anthracene, pyrene, coronene). First estimates the total cross sections in ion–PAH collisions display markedly...
We report on the first storage of ion beams in Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. have produced atomic carbon anions and small anion molecules (\documentclass[12pt]{minimal}\begin{document}${\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^-$\end{document}C2− molecular we...
The interaction of multiply charged ions (He${}^{2+}$, ${\mathrm{O}}^{3+}$, and Xe${}^{20+}$) with gas-phase pericondensed polycyclic aromatic hydrocarbon (PAH) molecules coronene (C${}_{24}$H${}_{12}$) pyrene (C${}_{16}$H${}_{10}$) is studied for low-velocity collisions ($v\ensuremath{\leqslant}0.6$ a.u.). mass spectrometric analysis shows that singly up to quadruply intact are important reaction products. relative experimental yields compared the results a simple classical over-the-barrier...
The present work combines experimental and theoretical studies of the collision between keV ion projectiles clusters pyrene, one simplest polycyclic aromatic hydrocarbons (PAHs). Intracluster growth processes induced by collisions lead to formation a wide range new molecules with masses larger than that pyrene molecule. efficiency these is found strongly depend on mass velocity incoming projectile. Classical molecular dynamics simulations entire process—from impact (nuclear scattering)...
Energetic ions lose some of their kinetic energy when interacting with electrons or nuclei in matter. Here, we discuss combined experimental and theoretical studies on such impulse driven reactions polycyclic aromatic hydrocarbons (PAHs), fullerenes, pure mixed clusters these molecules. These show that the nature excitation is important for how complex molecular systems respond to ion/atom impact. Rutherford-like nuclear scattering processes may lead prompt atom knockout formation highly...
Abstract This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics molecules clusters gas phase. It comprises nineteen contributions by scientists with leading expertise complementary experimental theoretical techniques to probe on timescales spanning twenty order magnitudes, from attoseconds minutes beyond, for systems ranging complexity smallest (diatomic) nanoparticles. Combining some these opens up new avenues unravel hitherto unexplored...
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...
We report the first experimental study of ions interacting with clusters polycyclic aromatic hydrocarbon (PAH) molecules. Collisions between 11.25 keV 3He+ or 360 129Xe20+ and weakly bound one smallest PAH molecules, anthracene, show that C14H10 have much higher tendencies to fragment in ion collisions than other clusters. The ionization is dominated by peripheral which clusters, very surprisingly, are more strongly heated Xe20+ He+ collisions. appearance size k=15 for [C ₁₄H₁₀](k)2+.
Helium adsorbed on $\mathrm{C}_{60}{}^{+}$ and $C_{70}{}^{+}$ exhibits phenomena akin to helium graphite. Mass spectra suggest that commensurate layers form when all carbon hexagons pentagons are occupied by one He each, but the solvation shell does not close until 60 atoms $\mathrm{C}_{60}{}^{+}$, or 62 $\mathrm{C}_{70}{}^{+}$. Molecular dynamics simulations of ${\mathrm{C}}_{60}\mathrm{He}_{n}{}^{+}$ at 4 K show phase is solid. added ${\mathrm{C}}_{60}\mathrm{He}_{32}{}^{+}$ will displace...
We report highly selective covalent bond modifications in collisions between keV alpha particles and van der Waals clusters of ${\mathrm{C}}_{60}$ fullerenes. Surprisingly, $\mathrm{C}_{119}{}^{+}$ $\mathrm{C}_{118}{}^{+}$ are the dominant molecular fusion products. use dynamics simulations to show that $\mathrm{C}_{59}{}^{+}$ $\mathrm{C}_{58}{}^{+}$ ions---effectively produced prompt knockout processes with ${\mathrm{He}}^{2+}$---react rapidly form dumbbell $\mathrm{C}_{118}{}^{+}$. Ion...
We present experimental evidence for the dominance of prompt single-atom knockout in fragmenting collisions between large polycyclic aromatic hydrocarbon cations and He atoms at center-of-mass energies close to 100 eV. Such nonstatistical processes are shown give highly reactive fragments. argue that fragmentation is dominant any sufficiently molecular system under similar conditions.
We have investigated the effectiveness of molecular hydrogen (H2) formation from Polycyclic Aromatic Hydrocarbons (PAHs) which are internally heated by collisions with keV ions. The present and earlier experimental results analyzed in view structure calculations a simple collision model. estimate that H2 becomes important for internal PAH temperatures exceeding about 2200 K, regardless size excitation agent. This suggests ions may effectively induce such reactions, while they unlikely due...
Fragmentation of singly charged anions adenosine 5'-monophosphate (AMP-) induced by collisions with neutral atoms (Ne, Na) has been studied at a collision energy 50 keV. The experiments were performed isolated AMP- as well nanosolvated in cluster given number m water molecules. In the first case, dominant fragmentation channels concern loss adenine, PO3- and H2PO4-. latter, molecules becomes dominating process, ion is fully protected when larger than approximately 13. observed fragment...
Electron-transfer and -capture dissociations of doubly protonated peptides gave dramatically different product ions for a series histidine-containing pentapeptides both non-tryptic (AAHAL, AHAAL, AHADL, AHDAL) tryptic (AAAHK, AAHAK, AHAAK, HAAAK, AAAHR, AAHAR, AHAAR, HAAAR) type. Electron transfer from gaseous Cs atoms fluoranthene anions triggered backbone all four N-C(alpha) bonds in the peptide addition to loss H NH(3). Substantial fractions charge-reduced cation-radicals did not...
A recent study of soft X-ray absorption in native and hydrogenated coronene cations, C$_{24}$H$_{12+m}^+$ $m=0-7$, led to the conclusion that additional hydrogen atoms protect (interstellar) Polycyclic Aromatic Hydrocarbon (PAH) molecules from fragmentation [Reitsma et al., Phys. Rev. Lett. 113, 053002 (2014)]. The present experiment with collisions between fast (30-200 eV) He pyrene (C$_{16}$H$_{10+m}^+$, $m=0$, 6, 16) simulations without reference excitation method suggests opposite. We...
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...
Naphthalene and azulene are isomeric polycyclic aromatic hydrocarbons (PAHs) topical in the context of astrochemistry due to recent discovery substituted naphthalenes Taurus Molecular Cloud-1 (TMC-1). Here, thermal- photo-induced isomerization, dissociation, radiative cooling dynamics energized (vibrationally hot) naphthalene (Np+) (Az+) radical cations, occurring over microsecond seconds timescale, investigated using a cryogenic electrostatic ion storage ring, affording “molecular cloud...
<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...
Indene (C$_9$H$_8$) is the only polycyclic pure hydrocarbon identified in interstellar medium to date, with an observed abundance orders of magnitude higher than predicted by astrochemical models. The dissociation and radiative stabilization vibrationally-hot indene cations investigated measuring time-dependent neutral particle emission rate from ions a cryogenic ion-beam storage ring for up 100~ms. Time-resolved measurements kinetic energy released upon hydrogen atom loss C$_9$H$_8^+$,...
An electrospray ion source has been coupled to a cryogenic electrostatic ion-beam storage ring enable experimental studies of the fundamental properties biomolecular ions and their reactions in gas phase on longer timescales than with previous instruments. Using this equipment, we have measured vibrational radiative cooling rate deprotonated anion chromophore cyan fluorescent protein, color-shifted mutant iconic green protein. Time-resolved dissociation rates collisionally activated are...
Clusters of fullerenes (C60,C70)(n) are produced in a gas aggregation source and multiply ionized collisions with highly charged Xe(20+,30+) ions. Their stabilities decay processes analyzed high-resolution time-of-flight mass spectrometry. Fullerene clusters charge states up to q=5 have been observed appearance sizes found be as small n(app)=5, 10, 21, 33 for q=2, 3, 4, 5, respectively. The analysis the multicoincident fragmentation spectra indicates high mobility. This is contrast...