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Structural and Electronic Properties of Hydrated VnH2O and Vn+H2O, n ≤ 13, Systems

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journal contribution
posted on 08.02.2017, 00:00 by Brandon Meza, Patricia Miranda, Miguel Castro
Water adsorption on small vanadium clusters, Vn–H2O and Vn+–H2O, n ≤ 13, is crucial to understanding the details of the metal-solvation process, very difficult to determine experimentally. Therefore, by means of density functional theory, BPW91-D2 all-electron calculations with dispersion corrections, the low-lying states of Vn and Vn+ are studied in this work, where dimer motifs, acting as basic building blocks, give origin to distorted structures. The results for Vn and Vn+ are consistent with experimental determinations for ionization energies (IE), dissociation energies, and IR spectra. We found that multiple isomers are involved in the spectrum of some Vn+ ions and that the IEs are reduced by water attachment in Vn–H2O. By means of metal–oxygen bonding, V–O, water adsorption is done on atop sites of the Vn+ cations. This is confirmed by the results of vibrational analysis, which are in agreement with reported experimental findings, revealing small blue and red shifts of the bending frequency of the adsorbed water molecule. In neutral Vn–H2O, hydrogen bonding also contributes. Notably, in V5–H2O, the metal atom lies in between the O and H atoms, forming agostic bonds, producing activation of the O–H bond: Vn clusters show some catalytic behavior in their interaction with water molecules.