2024-01-22

Department of Physics

The mutual neutralization of hydronium and hydroxide

Using the unique DESIREE facility, researchers at Stockholm University and The Hebrew University of Jerusalem have for the first time been able to directly visualise the neutral products of the mutual neutralization of hydronium and hydroxide, and report three different product channels: two channels were attributed to a predominant electron-transfer mechanism, and a smaller channel was associated with proton transfer. The two-beam collision experiment is an important step toward understanding the quantum dynamics of this fundamental reaction. Their findings are published in the journal Science. A team of scientists led by Prof. Daniel Strasser at The Hebrew University in Israel joined with a team led by Dr. Richard Thomas at The Department of Physics at Stockholm University, to investigate this reaction using the DESIREE facility.

Physics - Theme page

2024-01-18

Department of Physics

When Opposites Fatally Attract: The Mutual Neutralisation Story

One reaction involving atomic and molecular ions which is extremely difficult to measure and explore in detail is mutual neutralisation, where a positive ion and a negative ion meet up, and neutralise. Thanks to a unique ion storage ring device, DESIREE, in Stockholm Sweden, these oppositely charged ions can be stored and controlled, then merged together in a cryogenically cold environment where the MN reaction happens. Using a cutting edge camera, we identify the reaction products and reconstruct the moment these opposites became fatally attracted, and neutralised.

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2023-06-29

Department of Physics

Coronene molecules contribute to complex chemistry in space

Carbon forms the basis of all organic chemistry and thus the building blocks of life. There is increasing evidence that amino acids and other complex organic molecules can be formed in space and spread to planets through, e.g., comet impacts. Large carbon-based molecule such as coronene could play an important role in how such organic molecules are produced in astronomical environments. Michael Gatchell has been interested in understanding the universe for as long as he can remember. Here he tells us about his research at Atomic Physics division of Fysikum and new results can change how we imagine molecules such as coronene contribute to chemistry in space.

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2023-02-02

Department of Physics

Yet another breakthrough for researchers at DESIREE!

An international collaboration led by Mark H. Stockett (Fysikum) and James N. Bull (University of East Anglia) last week published results from experiments conducted at the DESIREE infrastructure at Fysikum in Nature Communications. After decades of speculation and searching, astronomers have recently begun to identify complex Polycyclic Aromatic Hydrocarbon (PAH) molecules in interstellar clouds.

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2022-10-12

Department of Physics

Precision electron affinity measurement in DESIREE

The electron affinity of an element is defined as the amount of energy released when an additional electron is bound to the system, which is—of course—equal to the energy needed to remove the negatively charged ion. An efficient way to determine electron affinities is to expose an ensemble of negative ions to a laser field and then vary the wavelength of the light to find the threshold for a signal relating to the photodetachment process separating an electron from the now neutralized atom. The longest wavelength where this happens corresponds to a photon energy equal to the electron affinity, so by finding the threshold and transforming from wavelength to photon energy one can determine the electron affinity.

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