Computational molecular dynamics simulations of cationic alkali dimers solvated in He clusters: the Li case

Raquel Yanes-Rodríguez; Raúl Rodríguez-Segundo; Pablo Villarreal; Rita Prosmiti

doi:10.1140/epjd/s10053-023-00691-9

2024 Impact factor 1.5

Atomic, Molecular, Optical and Plasma Physics

Dynamics and Photodynamics: from isolated molecules to the condensed phase

Eur. Phys. J. D (2023) 77: 116
https://doi.org/10.1140/epjd/s10053-023-00691-9

Regular Article – Clusters and Nanostructures

Computational molecular dynamics simulations of cationic alkali dimers solvated in He clusters: the Li $_{2}^{+}$ case

Raquel Yanes-Rodríguez, Raúl Rodríguez-Segundo, Pablo Villarreal^c and Rita Prosmiti^d

Instituto de Física Fundamental, IFF-CSIC, Serrano 123, 28006, Madrid, Madrid, Spain

^c p.villarreal@csic.es
^d rita@iff.csic.es

Received: 21 March 2023
Accepted: 30 May 2023
Published online: 22 June 2023

Abstract

The structures and energetics of Li $_{2}^{+}$ $$_2^+$$ -doped He clusters have been determined by means of evolutionary programming optimizations and classical molecular dynamics simulations. The underlying interactions in the He $_{N}$ $$_N$$ Li $_{2}^{+}$ complexes are described by sum-of-potentials ab initio-based models. The classical picture of the He atoms surrounding the cationic dimer shows a selective growth of the clusters. By analyzing spatial distribution probabilities, and single-atom evaporative energies from molecular dynamics calculations, we found pronounced drops in the computed energy for $N = 2$ $$N=2$$ , 4 and 6, and smaller ones for $N = 10$ $$N=10$$ , 13, 15, 18, 20, 22, 24, 27 and 29. The most energetic favored structure (compared to its neighbors) is found when six He atoms are attached in the Li $_{2}^{+}$ $$_2^+$$ -cation, forming He $_{3}$ $$_3$$ -motifs at each side and leading to the formation of the first solvation shell. In turn, as extra He atoms are added, a new shell is started to form at $N = 10$ $$N=10$$ , with the He $_{3}$ $$_3$$ triangles being the building blocks in all classical solid-like structural arrangements in He $_{N}$ $$_N$$ Li $_{2}^{+}$ $$_2^+$$ clusters. By combining the outcome of our work on the existence of such local solvation microstructures in Li $_{2}^{+}$ -doped He clusters together with those from previous studies on alkali ions, we may speculate that such microsolvation effects could influence the short-time solute–solvent dynamics and thus contribute to the observed slow ions’ mobility in He droplets.

T.I.: Dynamics and Photodynamics: from isolated molecules to the condensed phase.

Guest editors: Luis Bañares, Ramón Hernández-Lamoneda, Pascal Larregaray, Germán Rojas-Lorenzo, Jesús Rubayo-Soneira.

Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjd/s10053-023-00691-9.

Copyright comment Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.