The role played by the bosonic or fermionic character of He atoms surrounding a Br2(X) molecule is analyzed through vibrotational Raman spectra simulations. Quantum chemistry-type calculations reveal the spin multiplicity to be chiefly responsible for the drastic difference observed by Grebenev et al. [Science 279, 2083 (1998)]] in the rotational structure of molecules embedded in helium droplets.

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Enhanced thermoelectric performance of Cu3SbS4 with fine microstructure and optimized carrier concentration by Sn-doping.

The aim of this paper is to elucidate the role played by the bosonic/fermionic character of N He atoms solvating a Br2(X) molecule. To this end, an adiabatic model in the molecular stretching coordinate is assumed and the ground energy levels of the complexes are searched by means of Hartree (or Hartree-Fock) Quantum Chemistry calculations for 4He (or 3He) solvent atoms. Simulations of vib-rotational Raman spectra point at the spin multiplicity as the main feature responsible for the drastic difference in the rotational structures of molecules embedded in boson or fermion helium drops as already observed by the experiments of Grebenev et al. [S. Grebenev, J. P. Toennies, and A. F. Vilesov, Science 279 (1998) 2083].

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The adsorption of an oxygen molecule on nanoclusters of Pt and PtNi, in the size range between 13 and 55 atoms, has been studied using first-principle simulations. The structures have been obtained as a function of size and chemical composition of the clusters by means of the parallel excitable-walkers basin hopping method. O(2) preferentially adsorbs along the edge between two (111) facets due to a massive distortion of the Pt-Pt bond length. This bond elongation favours the adsorption in such a way that the binding energy of oxygen on a pure 55-atom cluster is still twice the value on the clean Pt(111). On the other hand, on 55-Pt(shell)Ni(core) nanoparticles, the O(2) binding energy is slightly lower than on Pt(111), because nickel core inhibits the stretching of the Pt-bond because of their size mismatch. However, as soon as its concentration is increased, Ni appears at the surface and its oxyphilic nature contributes to bind the oxygen molecule stronger.

The structural properties and the energetics of some of the smaller ionic clusters of neon atoms with the atomic impurity H−, NenH− with n from 2 up to 8, are examined using different kinds of modeling for the interactions within each cluster and employing different theoretical dynamical approaches, both classical and quantal. The same calculations are carried out also for the corresponding neutral homogeneous clusters Nen+1. The results of the calculations, the physical reliability of the interaction modeling, and the similarities between different features shown by the negative ions with respect to the neutral complexes are discussed. The emerging picture shows that the dopant atom H− always locates itself outside the Nen moiety for clusters of this size without significantly affecting the overall geometries and that many-body (MB) effects within the clusters are rather negligible in the description of the overall interaction potentials.

A structural study of the smaller Li(+)Hen clusters with n ≤ 30 has been carried out using different theoretical methods. The structures and the energetics of the clusters have been obtained using both classical energy minimization methods and quantum Diffusion Monte Carlo. The total interaction acting within the clusters has been obtained as a sum of pairwise potentials:  Li(+)-He and He-He. This approximation had been shown in our earlier study to give substantially correct results for energies and geometries once compared to full ab initio calculations. The general features of the spatial structures, and their energetics, are discussed in details for the clusters up to n = 30, and the first solvation shell is shown to be essentially completed by the first 8-10 helium atoms.