Study of the structural properties of clusters [Mo6X14] (X = F, Cl, Br, I) at 22 EM and the second ionization energy of clusters [Mo6X14]2- by the density functional method

Abstract

The structural properties of the clusters Mo₆X₁₄ (X = F, Cl, Br, I) at 22 EM were studied by the density functional method at the theoretical level PBE/TZ2P, taking into account the the scalar relative effect in the ZORA approximation and the spin-orbit coupling, in singlet and triplet spin configurations. The calculations showed that the bromide cluster is stable in C_2v symmetry and the iodide cluster is stable in D_4h symmetry corresponding to the high spin configuration while the Mo₆Cl₁₄ cluster is stable in C_s symmetry for the low spin configuration. The large distortion in the metallic core of the fluoride cluster has been demonstrated and that of the studied clusters decreases from fluoride to iodide. The calculation results of the second ionization energy of the clusters [Mo₆X₁₄]^2- (X = Cl, Br, I) show that the second ionization energy is much higher than the first ionization energy, which causes great difficulty in oxidizinggreat these ions to obtain neutral molecules.