Chapter 3
Metal Cluster Reacting with Oxygen
Cluster-oxygen reactions on metal and metal-alloy systems have been widely investigated [1–6] Through reactions with oxygen (a strong etchant), several interesting
clusters of metals (e.g., magnesium, aluminium and their alloys) with resistence to
oxygen etching have been identified as magic species, even though bulk metals of
these clusters are highly reactive [7–10] These magic species (at closed electron
shells) are also marked by large HOMO–LUMO gaps, high atom-removal energies
(or, fragmentation energies), spin excitation energies and/or ionization energies [11,
12]. Advances in this field have been intensified not only because of the importance
of cluster reactions with oxygen providing insights into the reactivity and property
of metals at reduced sizes, but also enabling using the knowledge gained through
gas-phase reactivity of metal clusters to facilitate the understanding of interdisciplinary frontiers including condensed phase physics and surface chemistry. This
chapter
1 will highlight the oxygen etching effect and oxygen-addition reactions,
cluster odd–even alternation phenomenon, as well as superoxo and peroxo states
involved in metal cluster reactivity with oxygen.
3.1 Oxygen Etching Effect
The observation of oxygen etching effect dates back to very early cluster investigations. Figure 3.1 shows one of the earliest cluster reaction studies between aluminum
and oxygen by Jarrold and Bower in 1986 [13]. In this study, the cationic clusters
Al n
+ (n = 4–25) were generated by a LaVa source, ionized by a high-energy electron
beam and expanded into the vacuum system where specific cluster sizes were massselected by a quadrupole mass filter; focused into a low-energy ion beam and then
1 This chapter is partly reproduced from Chem. Rev. 2016, 116, 14456–14492.
© The Editor(s) (if applicable) and The Author(s), under exclusive license
to Springer Nature Singapore Pte Ltd. 2020
Z. Luo and S. N. Khanna, Metal Clusters and Their Reactivity,
https://doi.org/10.1007/978-981-15-9704-6_3
39
Metal Cluster Reacting with Oxygen
Cluster-oxygen reactions on metal and metal-alloy systems have been widely investigated [1–6] Through reactions with oxygen (a strong etchant), several interesting
clusters of metals (e.g., magnesium, aluminium and their alloys) with resistence to
oxygen etching have been identified as magic species, even though bulk metals of
these clusters are highly reactive [7–10] These magic species (at closed electron
shells) are also marked by large HOMO–LUMO gaps, high atom-removal energies
(or, fragmentation energies), spin excitation energies and/or ionization energies [11,
12]. Advances in this field have been intensified not only because of the importance
of cluster reactions with oxygen providing insights into the reactivity and property
of metals at reduced sizes, but also enabling using the knowledge gained through
gas-phase reactivity of metal clusters to facilitate the understanding of interdisciplinary frontiers including condensed phase physics and surface chemistry. This
chapter
1 will highlight the oxygen etching effect and oxygen-addition reactions,
cluster odd–even alternation phenomenon, as well as superoxo and peroxo states
involved in metal cluster reactivity with oxygen.
3.1 Oxygen Etching Effect
The observation of oxygen etching effect dates back to very early cluster investigations. Figure 3.1 shows one of the earliest cluster reaction studies between aluminum
and oxygen by Jarrold and Bower in 1986 [13]. In this study, the cationic clusters
Al n
+ (n = 4–25) were generated by a LaVa source, ionized by a high-energy electron
beam and expanded into the vacuum system where specific cluster sizes were massselected by a quadrupole mass filter; focused into a low-energy ion beam and then
1 This chapter is partly reproduced from Chem. Rev. 2016, 116, 14456–14492.
© The Editor(s) (if applicable) and The Author(s), under exclusive license
to Springer Nature Singapore Pte Ltd. 2020
Z. Luo and S. N. Khanna, Metal Clusters and Their Reactivity,
https://doi.org/10.1007/978-981-15-9704-6_3
39