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Principles of isomer stability in small clusters

In this work we study isomers of several representative small clusters to find principles for their stability. Our conclusions about the principles underlying the structure of clusters are based on a huge database of 44 000 isomers generated for 58 different clusters on the density functional theory...

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Autores principales: Fisicaro, Giuseppe, Schaefer, Bastian, Finkler, Jonas A., Goedecker, Stefan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: RSC 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10068428/
https://www.ncbi.nlm.nih.gov/pubmed/37026041
http://dx.doi.org/10.1039/d2ma01088g
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author Fisicaro, Giuseppe
Schaefer, Bastian
Finkler, Jonas A.
Goedecker, Stefan
author_facet Fisicaro, Giuseppe
Schaefer, Bastian
Finkler, Jonas A.
Goedecker, Stefan
author_sort Fisicaro, Giuseppe
collection PubMed
description In this work we study isomers of several representative small clusters to find principles for their stability. Our conclusions about the principles underlying the structure of clusters are based on a huge database of 44 000 isomers generated for 58 different clusters on the density functional theory level by Minima Hopping. We explore the potential energy surface of small neutral, anionic and cationic isomers, moving left to right across the third period of the periodic table and varying the number of atoms n and the cluster charge state q (X(q)(n), with X = {Na, Mg, Al, Si, Ge}, q = −1, 0, 1, 2). We use structural descriptors such as bond lengths and atomic coordination numbers, the surface to volume ratios and the shape factor as well as electronic descriptors such as shell filling and hardness to detect correlations with the stability of clusters. The isomers of metallic clusters are found to be structure seekers with a strong tendency to adopt compact shapes. However certain numbers of atoms can suppress the formation of nearly spherical metallic clusters. Small non-metallic clusters typically also do not adopt compact spherical shapes for their lowest energy structures. In both cases spherical jellium models are not any more applicable. Nevertheless for many structures, that frequently have a high degree of symmetry, the Kohn–Sham eigenvalues are bunched into shells and if the available electrons can completely fill such shells, a particularly stable structure can result. We call such a cluster whose shape gives rise to shells that can be completely filled by the number of available electrons an optimally matched cluster, since both the structure and the number of electrons must be special and match. In this way we can also explain the stability trends for covalent silicon and germanium cluster isomers, whose stability was previously explained by the presence of certain structural motifs. Thus we propose a unified framework to explain trends in the stability of isomers and to predict their structure for a wide range of small clusters.
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spelling pubmed-100684282023-04-04 Principles of isomer stability in small clusters Fisicaro, Giuseppe Schaefer, Bastian Finkler, Jonas A. Goedecker, Stefan Mater Adv Chemistry In this work we study isomers of several representative small clusters to find principles for their stability. Our conclusions about the principles underlying the structure of clusters are based on a huge database of 44 000 isomers generated for 58 different clusters on the density functional theory level by Minima Hopping. We explore the potential energy surface of small neutral, anionic and cationic isomers, moving left to right across the third period of the periodic table and varying the number of atoms n and the cluster charge state q (X(q)(n), with X = {Na, Mg, Al, Si, Ge}, q = −1, 0, 1, 2). We use structural descriptors such as bond lengths and atomic coordination numbers, the surface to volume ratios and the shape factor as well as electronic descriptors such as shell filling and hardness to detect correlations with the stability of clusters. The isomers of metallic clusters are found to be structure seekers with a strong tendency to adopt compact shapes. However certain numbers of atoms can suppress the formation of nearly spherical metallic clusters. Small non-metallic clusters typically also do not adopt compact spherical shapes for their lowest energy structures. In both cases spherical jellium models are not any more applicable. Nevertheless for many structures, that frequently have a high degree of symmetry, the Kohn–Sham eigenvalues are bunched into shells and if the available electrons can completely fill such shells, a particularly stable structure can result. We call such a cluster whose shape gives rise to shells that can be completely filled by the number of available electrons an optimally matched cluster, since both the structure and the number of electrons must be special and match. In this way we can also explain the stability trends for covalent silicon and germanium cluster isomers, whose stability was previously explained by the presence of certain structural motifs. Thus we propose a unified framework to explain trends in the stability of isomers and to predict their structure for a wide range of small clusters. RSC 2023-02-28 /pmc/articles/PMC10068428/ /pubmed/37026041 http://dx.doi.org/10.1039/d2ma01088g Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/
spellingShingle Chemistry
Fisicaro, Giuseppe
Schaefer, Bastian
Finkler, Jonas A.
Goedecker, Stefan
Principles of isomer stability in small clusters
title Principles of isomer stability in small clusters
title_full Principles of isomer stability in small clusters
title_fullStr Principles of isomer stability in small clusters
title_full_unstemmed Principles of isomer stability in small clusters
title_short Principles of isomer stability in small clusters
title_sort principles of isomer stability in small clusters
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10068428/
https://www.ncbi.nlm.nih.gov/pubmed/37026041
http://dx.doi.org/10.1039/d2ma01088g
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