A superatomic molecule under the spin-orbit coupling. Insights from the electronic properties in the thiolate-protected Au38(SR)24 cluster

International Journal of Quantum Chemistry

3 years ago

A superatomic molecule under the spin-orbit coupling. Insights from the electronic properties in the thiolate-protected Au38(SR)24 cluster

Alvaro Muñoz-Castro

The role of the spin-orbit coupling in Au38(SR)24, as a representative case for a superatomic molecules is studied to offer a complete view of the relativistic effect in heavy elements clusters. Its Au239+ core can be described in as an analog to a diatomic molecule, such as F2, allowing the electronic structure to be depicted in terms of the D∞h point group. First, we showed the electronic structure under the spin-orbit framework using total angular momentum representations (j = ℓ ± s; spinors), which allows us to characterize the expected splitting of certain levels derived from the cluster core. Accordingly, the optical properties are evaluated under spin-orbit coupling regime, revealing differences in the low-energy region of the absorption spectrum. Lastly, the variation of electron affinity (EA) and ionization potential (IP) properties is evaluated. This reveals characteristic consequences of the inclusion of spin-orbit coupling in Au38(SR)24, as a bridge to larger thiolate-protected gold clusters. The inclusion of the spin-orbit coupling in a superatomic molecule case given by Au38(SR)24, exposes the role of the relativistic effect in electronic, optical, and electron affinity properties. The HOMO-LUMO gap is decreased, revealing a further splitting of the expected absorption bands. The use of double-point groups gave a clear understanding of the molecular properties under the spin-orbit coupling regime, which can be extended to other heavy-element clusters.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/qua.25508