Metallic nanoclusters, with one electron or hole difference from closed shell, might end up in a degenerate state undergoing a Jahn–Teller distortion as a result of nonadiabatic effects, which are a manifestation of the electron–vibron coupling. Here, we report a theoretical study on the stability and nonadiabaticity of the neutral and charged endohedral clusters X@Al12 (X = B, C, N, Al, Si, P) around icosahedral symmetry, for 39, 40, and 41 valence electrons. The nonadiabatic effects are evaluated through the Jahn–Teller gain for the distorted cluster and their effect on the calculated electronic density of states is analyzed. For the 40 electron valence systems, we present the full vibrational spectra. Our results are discussed within the framework of the superatom model, and show that not all systems are well described by the spherical jellium model and that nonadiabaticity is better represented by ellipsoidal models. We present a detail discussion of the Al13 –1 electron detachment process and show how, through a comparison with available experimental photoelectron spectroscopy data, the nonadiabaticity can be estimated.

Silicene, the graphene-like crystal formed by the Si hexagonal lattice, presents a periodic buckled structure whose origin is due to the pseudo Jahn-Teller instability on each of its planar six membered rings. This has been attributed to the coupling of the planar D6h ground state with the first b2g excited state through a b2g vibrational mode. Here we show, by explicitly calculating the vibronic coupling constants through a complete study of the PJT effect, that the vibronic coupling of the ground state with only one excited state to explain the planar instability is inconsistent with the linear multilevel PJT effect theory. It is also shown that in order to have consistency, the PJT model should include the next excited state, which is symmetry compatible coupled to the puckering mode. This is done by the analysis, based on DFT and TDDFT calculations, of the vibronic instability of the ground state of hexasilabenzene, the basic silicon hydrogenated hexagonal ring unit defining silicene.

In this work we present the results of relativistic DFT calculations of magnetic moments for manganese inserted into a gold ring (Mn@Au6) or a cage-like structure (Mn@Au12) both pristine and n-thiolated. Optimization has been carried out to obtain different isomers always favouring the endohedral gold clusters with Mn inside. For the total magnetic moment (from electronic population analysis) verification of the jellium model has been performed in each case. It is concluded that the magnetic moments arise largely from the doped manganese atom and that thiolation can modulate its value, which is not present in the pure form. In the Mn@Au12 clusters we observed the formation of a hole in their structure; this could be a characteristic of insertion of a highly ferromagnetic dopant in some metal clusters, such as gold, and this could act as a precursor of the formation of gold magnetic nanotubes.

The search for a catalyst for the reduction of nitrous oxide (NO) is now imperative, as this molecule is a very dangerous pollutant. We found that the low-symmetry Pt cluster presents multiple reaction pathways for NO rupture, which are regioselective. This result was revealed by means of density functional theory calculations within the zero-order-regular approximation, ZORA, explicitly including relativistic effects. It is further proved that Pt is a competitive NO catalyst compared to sub-nanometric rhodium clusters, obtaining similar reaction barriers. The hot adsorption site, a tip atom of Pt, and the rotation of the NO molecule over the metallic cluster promote the formation of a frustrated bridge activated transition state, Pt-NO. This transition structure yields to spontaneous dissociation of NO without bridge formation. Along this catalytic process, rearrangements within the metal cluster take place, preserving its stability. Moreover, in addition to being important attributes of the Pt particle in the NO reduction, fluxionality and multiple reaction pathways may also prevent poisoning effects. Overall, this differs from reported results for more symmetric metal particles also used as catalysts.