Publications by authors named "Ansgar Simonsson"
Article Synopsis
- The study investigates the reaction between vibronically cold NO^{+} and O^{-} at a low collision energy of about 0.1 eV, focusing on single-collision interactions.
- The reaction primarily results in the formation of three ground-state atomic fragments.
- Using product-momentum analysis, the researchers propose a two-step mechanism where the anion donates an electron, leading to an intermediate Rydberg state of NO that eventually breaks apart.
Article Synopsis
- The study focuses on the mutual neutralization reaction between hydronium (HO) and hydroxide (OH) ions, which is a basic yet not well-understood chemical process.
- Using advanced imaging techniques in a cryogenic ion storage facility, researchers observed the products formed during these reactions at low collision energies.
- The findings reveal that most of the reactions involve electron-transfer mechanisms, while some also involve proton transfer, helping to create a basis for future modeling of charge-transfer processes.
Article Synopsis
- The article DOI: 10.1103/PhysRevLett.128.033401 has been updated or amended.
- The corrections are important for accurate interpretation of the research findings.
- Readers should refer to the corrected version for the most reliable information.
Article Synopsis
- Negative ions play a crucial role in various scientific fields such as interstellar chemistry and anti-matter research, where their unique properties are influenced by electron-correlation effects.
- Traditional methods for studying these ions face challenges due to their loosely bound nature and limited optical transitions, hindering high-resolution detection techniques.
- A new method has been developed that accurately measures negative ion binding energies with significantly higher precision, utilizing laser manipulation and a cryogenic ion-beam storage ring, leading to a reported electron affinity of 1.461 112 972(87) eV for oxygen.
Article Synopsis
- Researchers examined how HfF and WF molecular anions decay spontaneously and when exposed to different laser wavelengths in a specialized facility called DESIREE, observing these processes over long time scales thanks to very low temperatures and pressures.
- The study found that both anions experience decay through electron detachment or fragmentation, with WF anions showing a significant increase in neutralization at a specific energy threshold of about 3.5 eV, while HfF did not exhibit any enhancement in neutrons produced, even at high energy levels.
- This finding could aid in improving the detection of the rare isotope Hf in accelerator mass spectrometry by minimizing interference from stable isobar W, which is important for astrophysical studies on nucleosynthesis
Article Synopsis
- - The study investigates how Mg atoms are generated from reactions between Mg^{+} and D^{-} at low collision energies (around 59 meV) using a specific experimental method.
- - The results show significant differences when compared to previous full-quantum theories, indicating that past calculations have underestimated the total reaction rate by nearly double in low-energy scenarios.
- - The researchers suggest that using asymptotic model calculations provides more accurate results and advocate for applying this approach to study more complicated systems, which is important for understanding stellar conditions.
Article Synopsis
- Laboratory experiments help us understand the interstellar medium (ISM), but matching lab findings with cosmic reactions is challenging due to different timescales.
- This study focuses on the reactive fragments of coronene, a type of polycyclic aromatic hydrocarbon (PAH), after they collide with helium atoms at high speeds.
- Results indicate that these damaged PAH fragments can remain stable and influential in the ISM over long periods, potentially affecting interstellar chemistry due to their enhanced reactivity.
The mutual neutralisation of O with O has been studied in a double ion-beam storage ring with combined merged-beams, imaging and timing techniques. Branching ratios were measured at the collision energies of 55, 75 and 170 (± 15) meV, and found to be in good agreement with previous single-pass merged-beams experimental results at 7 meV collision energy. Several previously unidentified spectral features were found to correspond to mutual neutralisation channels of the first metastable state of the cation (O(D), ≈ 3.
View Article and Find Full Text PDFAn investigation into the dissociative recombination process for H(13)CO(+) using merged ion-electron beam methods has been performed at the heavy ion storage ring CRYRING, Stockholm, Sweden. We have measured the branching fractions of the different product channels at ∼ 0 eV collision energy to be the following: CO + H 87 ± 2%, OH + C 9 ± 2%, and O + CH 4 ± 2%. The formation of electronically excited CO in the dominant reaction channel has also been studied, and we report the following tentative branching fractions for the different CO product electronic states: CO(X (1)Σ(+)) + H, 54 ± 10%; CO(a (3)Π) + H, 23 ± 4%; and CO(a' (3)Σ(+)) + H, 23 ± 4%.
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