The role of the electronic structure on the optical absorption, reactivity and thermal radiation of small clusters in the gas phase

One of the most attractive features of small clusters in the gas phase is that their properties depend strongly on size and composition. The dream of the cluster community is to identify some particular clusters with unique properties, and be able to deposit these species and use them in specialized devices. For this to happen, however, a deep understanding of the effects of cluster size and composition on the different properties of the system is needed. In the past years several studies, using both experimental and theoretical approaches, have been devoted to study different systems of clusters and investigate how their properties are affected by changing size and composition. Moreover, it is also known in this respect that most clusters’ properties, such as stabilities, reactivities and optical responses, are directly or indirectly related with the system’s electronic structure. For example, clusters with filled shells of delocalized electrons tend to be more stable than their neighboring sizes. Also, clusters having orbitals of the right symmetry can bind strongly to molecules such as CO or O2. Furthermore, clusters with different electronic levels will absorb light at different wavelengths. Therefore, to some extent, correlations between different properties are expected. This, however, has not been investigated in detail and clusters’ properties are usually studied independently. The main goal of this work is to investigate three main clusters’ properties with a focus on their direct or indirect relation with the system’s electronic structure, thus expecting to find correlations between them. In particular, this work focuses on the reactivity towards CO, the optical absorption in the UV/visible range and the emission of radiation of highly excited species. For this purpose, different systems of clusters have been selected, allowing the possibility to probe the effect of size and composition on the aforementioned properties. Even though the main focus of this work is experimental, in several parts density functional theory calculations are used to gain a deeper understanding of the investigated systems.status: publishe