FULL PAPER Symmetry lowering by cage doping in spherical superatoms: Evaluation of electronic and optical properties of 18-electron W@Au 12 Pt n (n = 0-4) superatomic clusters from relativistic DFT calculations Franck Gam 1,2 | Ramiro Arratia-Perez 1 | Samia Kahlal 2 | Jean-Yves Saillard 2 | Alvaro Muñoz-Castro 3 1 Doctorado en Fisicoquímica Molecular, Universidad Andres Bello, Santiago, Chile 2 Univ Rennes, CNRS, ISCR-UMR 6226, Rennes, France 3 Grupo de Química Inorgánica y Materiales Moleculares, Facultad de Ingenieria, Universidad Autonoma de Chile, Santiago, Chile Correspondence Ramiro Arratia-Perez, Doctorado en Fisicoquímica Molecular, Universidad Andres Bello, República 275, Santiago, Chile. Email: rarratia@unab.cl; Jean-Yves Saillard, Univ Rennes, CNRS, ISCR-UMR 6226, F-35000 Rennes, France. Email: saillard@univ-rennes1.fr and Alvaro Muñoz-Castro, Grupo de Química Inorgánica y Materiales Moleculares, Facultad de Ingenieria, Universidad Autonoma de Chile, El Llano Subercaseaux 2801, Santiago, Chile. Email: alvaro.munoz@uautonoma.cl Funding information GENCI-CINES and GENCI-IDRISS, Grant/ Award Number: a0010807367; Région Bretagne; FONDECYT, Grant/Award Number: 1180683 Abstract Attempts to expand the versatility of well defined clusters are a relevant issue in the design of building blocks for functional nanostructures. Here, we investigate the plausible forma- tion of related structures from the emblematic highly symmetrical 18-e [W@Au 12 ] cluster. The calculated [W@Au 12 Pt n ] series, with n = 0, 1, 2, 3, and 4, show cohesion energies, HOMO-LUMO gap, adiabatic electron affinities (AEAs) and adiabatic ionization potentials (AIPs), indicating a relative stability to the parent cluster [W@Au 12 ] experimentally charac- terized, where clusters with n = 1 and n = 4 are suggested as the most stable with respect to oxidation. The resulting symmetry lowering away from the high icosahedral symmetry upon adding Pt atoms induces a sizable splitting of the frontiers shells, which in turn effec- tively modify the properties of the calculated clusters, as observed from calculated optical properties. The estimated absorption spectra show an interesting broadening effect of the absorption peaks, which appears as a useful approach for further design of broad black absorbers, which are able to absorb light in a wider range, with potential capabilities to enhance the efficiency of thin film solar cells and photocatalysis processes, among other applications. KEYWORDS endohedral, gold, heteroatomic, platinum, superatoms 1 | INTRODUCTION Gold nanostructures are a fundamental concern in nanoscience, owing to their potential to serve as useful building blocks toward the design of novel materials with variable sizes displaying novel properties for catalysis, nanoelectronics, and biological diagnostics, [1–7] among other applications. [7–10] The efficiency in catalysts for carbon monoxide oxidation unraveled for discrete clusters is a relevant example of the differences between the inert bulk and clusters with precise numbers of gold atoms. [11–13] The current synthetic control to achieve nanoparticles [14–22] with selected atomic precision provides valuable opportunities to gain deeper knowledge of the structure-property relationship at regimes involving a few metallic atoms. Gold chemistry possesses a rich structural diversity owing to the particular role of relativistic effects, [23–28] resulting in unusual structures, highlighting the tetrahedral Au 20 cluster, [29–32] and the hollow Au 32 cage cluster. [33–35] Furthermore, the doping of heteroatoms into the gold Received: 4 July 2018 Revised: 31 August 2018 Accepted: 13 September 2018 DOI: 10.1002/qua.25827 Int J Quantum Chem. 2018;e25827. wileyonlinelibrary.com/journal/qua © 2018 Wiley Periodicals, Inc. 1 of 8 https://doi.org/10.1002/qua.25827