# Interatomic Coulombic decay in low energy ion-dimer collisions

W. Iskandar, J. Matsumoto, A Leredde, X. Fléchard, S. Guillous, C.L. Zhou, Jimmy Rangama, A. Méry, B. Gervais, D. Hennecart, et al.

► To cite this version:

W. Iskandar, J. Matsumoto, A Leredde, X. Fléchard, S. Guillous, et al. Interatomic Coulombic decay in low energy ion-dimer collisions. XXIX International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC2015), Jul 2015, Tolède, Spain. pp.032105, 10.1088/1742-6596/635/3/032105. in2p3-01294686

HAL Id: in2p3-01294686

https://hal.in2p3.fr/in2p3-01294686

Submitted on 23 May 2024

**HAL** is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

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<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Interatomic Coulombic decay in low energy ion-dimer collisions

W. Iskandar, J. Matsumoto, A. Leredde, X. Fléchard, S. Guillous, C.L. Zhou, Jimmy Rangama, A. Méry, B. Gervais, D. Hennecart, et al.

► To cite this version:

W. Iskandar, J. Matsumoto, A. Leredde, X. Fléchard, S. Guillous, et al. Interatomic Coulombic decay in low energy ion-dimer collisions. XXIX International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC 2015), Jul 2015, Tolède, Spain. pp.032105, 10.1088/1742-6596/635/3/032105. in2p3-01294686

HAL Id: in2p3-01294686

https://in2p3.hal.science/in2p3-01294686v1

Submitted on 23 May 2024

**HAL** is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
PAPER • OPEN ACCESS

# Interatomic Coulombic Decay in Low Energy Ion-Dimer Collisions

To cite this article: W Iskandar et al 2015 *J. Phys.: Conf. Ser.* **635** 032105

View the [article online](#) for updates and enhancements.

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# Interatomic Coulombic Decay in Low Energy Ion-Dimer Collisions

To cite this article: W Iskandar et al 2015 *J. Phys.: Conf. Ser.* **635** 032105

View the [article online](#) for updates and enhancements.

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electrochemistry & solid
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# Interatomic Coulombic Decay in Low Energy Ion-Dimer Collisions

W. Iskandar*<fnref n="1" />, J. Matsumoto§, A. Leredde†, X. Fléchard‡, S. Guillous*, C. L. Zhou*, J. Rangama*, A. Méry*, B. Gervais*, D. Hennecart*, H. Shiromaru§ and A. Cassimi*

* CIMAP, CEA-CNRS-ENSICAEN-Université de Caen, BP 5133, F-14070 Caen cedex 5, France

§ Departement of Chemistry, Tokyo Metropolitan University, Hachiouji-shi, Tokyo 192-0397, Japan

† Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

‡ LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, 14050 Caen Cedex 04, France

**Synopsis** Low energy collisions between ions and neon dimers are investigated, focusing attention on the dissociation of the ionized molecular target. The results show a clear dependance of the processes with the projectile charge state and an unexpected appearance of inner-shell single electron capture from one site of the neon dimer leading to interatomic coulombic decay process and low energy electrons emission.

Interaction of slow multi-charged ions (MCIs) with dimers is of great interest in various scientific fields, not only to study the electron capture by the projectile, but also to have access to insightful information about the target and its relaxation processes [1, 2, 3]. We present here an experimental and theoretical study of collisions between MCIs and Ne dimers including the identification and analysis of the possible processes.

The experiment was performed at GANIL facility (Caen, France), on the low energy beam line. Three different projectiles $O^{3+}$, $Ar^{9+}$ and $Xe^{20+}$, produced by an ECR ion source and accelerated to 15 qkeV, were used to collide with neon dimers provided by a supersonic jet. A COLTRIMS setup with multi-hit capability combined with a position-sensitive detector for scattered projectiles were employed to measure, in multi-coincidence, the projectile final charge state, the position and the time-of-flight of the ionic fragments. These measurements give access to the ionic fragments momentum and thus to the kinetic energy release (KER). The latter can be directly related to the internuclear distance prior dissociation (fig.1).

In the symmetric $Ne^{+} + Ne^{+}$ fragmentation channel, we have identified three different competing processes [3] illustrated in fig.1. Beside the direct coulomb explosion (CE), wherein the projectile captures one electron from each center of the dimer which directly dissociates, two other electronic relaxation mechanisms were observed: the interatomic coulombic decay (ICD) and the radiative charge transfer (RCT). The ICD process results from the single capture of an electron from the 2s inner valence state by the projectile. Then, the excited ion decays to $Ne^{+} (2p^{-1})$. The excess energy is transferred to the neighboring atom of the dimer by ejecting an outer valence

electron from the 2p state, causing molecular ion fragmentation. For the RCT process, two electrons from the outer valence states of one center of the dimer are first captured by the projectile. Electron transfer from the doubly ionized center to the neutral one can then occur by photon emission leading to molecular dissociation into two $Ne^{+} (2p^{-1})$ ions.

<figure><img src="image_5.png" /><figcaption>**Figure 1.** Illustration of the CE, RCT, and ICD processes in collisions between MCIs and Ne dimers.</figcaption></figure>

For these three processes, the dependance on the initial and final projectile charge state [3] and, on the angular correlation between projectile scattering direction and dimer orientation has also been investigated, providing further insight into the dynamics of the collision.

## References

[1] J. Matsumoto et al. 2010, Phys. Rev. Lett. 105 263202

[2] W. Iskandar et al. 2014, Phys. Rev. Lett. 113 143201

[3] W. Iskandar et al. 2015, Phys. Rev. Lett. 114 033201

<figure><img src="image_6.png" /></figure>

<footnote n="1">¹E-mail: iskandar@ganil.fr</footnote>
# Interatomic Coulombic Decay in Low Energy Ion-Dimer Collisions

W. Iskandar*<fnref n="1" />, J. Matsumoto§, A. Leredde†, X. Fléchard‡, S. Guillous*, C. L. Zhou*, J. Rangama*, A. Méry*, B. Gervais*, D. Hennecart*, H. Shiromaru§ and A. Cassimi*

* CIMAP, CEA-CNRS-ENSICAEN-Université de Caen, BP 5133, F-14070 Caen cedex 5, France

§ Departement of Chemistry, Tokyo Metropolitan University, Hachiouji-shi, Tokyo 192-0397, Japan

† Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

‡ LPC Caen, ENSICAEN, Université de Caen, CNRS/IN2P3, 14050 Caen Cedex 04, France

**Synopsis** Low energy collisions between ions and neon dimers are investigated, focusing attention on the dissociation of the ionized molecular target. The results show a clear dependance of the processes with the projectile charge state and an unexpected appearance of inner-shell single electron capture from one site of the neon dimer leading to interatomic coulombic decay process and low energy electrons emission.

Interaction of slow multi-charged ions (MCIs) with dimers is of great interest in various scientific fields, not only to study the electron capture by the projectile, but also to have access to insightful information about the target and its relaxation processes [1, 2, 3]. We present here an experimental and theoretical study of collisions between MCIs and Ne dimers including the identification and analysis of the possible processes.

The experiment was performed at GANIL facility (Caen, France), on the low energy beam line. Three different projectiles $O^{3+}$, $Ar^{9+}$ and $Xe^{20+}$, produced by an ECR ion source and accelerated to 15 qkeV, were used to collide with neon dimers provided by a supersonic jet. A COLTRIMS setup with multi-hit capability combined with a position-sensitive detector for scattered projectiles were employed to measure, in multi-coincidence, the projectile final charge state, the position and the time-of-flight of the ionic fragments. These measurements give access to the ionic fragments momentum and thus to the kinetic energy release (KER). The latter can be directly related to the internuclear distance prior dissociation (fig.1).

In the symmetric $Ne^{+} + Ne^{+}$ fragmentation channel, we have identified three different competing processes [3] illustrated in fig.1. Beside the direct coulomb explosion (CE), wherein the projectile captures one electron from each center of the dimer which directly dissociates, two other electronic relaxation mechanisms were observed: the interatomic coulombic decay (ICD) and the radiative charge transfer (RCT). The ICD process results from the single capture of an electron from the 2s inner valence state by the projectile. Then, the excited ion decays to $Ne^{+} (2p^{-1})$. The excess energy is transferred to the neighboring atom of the dimer by ejecting an outer valence

electron from the 2p state, causing molecular ion fragmentation. For the RCT process, two electrons from the outer valence states of one center of the dimer are first captured by the projectile. Electron transfer from the doubly ionized center to the neutral one can then occur by photon emission leading to molecular dissociation into two $Ne^{+} (2p^{-1})$ ions.

<figure><img src="image_5.png" /><figcaption>**Figure 1.** Illustration of the CE, RCT, and ICD processes in collisions between MCIs and Ne dimers.</figcaption></figure>

For these three processes, the dependance on the initial and final projectile charge state [3] and, on the angular correlation between projectile scattering direction and dimer orientation has also been investigated, providing further insight into the dynamics of the collision.

## References

[1] J. Matsumoto et al. 2010, Phys. Rev. Lett. 105 263202

[2] W. Iskandar et al. 2014, Phys. Rev. Lett. 113 143201

[3] W. Iskandar et al. 2015, Phys. Rev. Lett. 114 033201

<figure><img src="image_6.png" /></figure>

<footnote n="1">¹E-mail: iskandar@ganil.fr</footnote>