Nature of hydrogen interaction and saturation on small titanium clusters

This work explores the nature of interaction and saturation of hydrogen molecules on small titanium clusters using ab initio calculations. Molecular dynamics simulations and ensuing charge density maps were used to gain insight into the key steps involved in dissociation of the hydrogen molecule on the metal clusters. The mechanistic insights gleaned from these simulations were subsequently utilized to obtain realistic models of the hydrogen saturated titanium clusters. It was found that the most stable hydrogen saturated titanium clusters involve hydrogen multicenter bonds. The observed peaks in the experimental mass and photoelectron spectra of hydrogen saturated titanium clusters are attributed to structures possessing hydrogen multicenter bonds. Hydrogen multicenter bonds are also ascribed to the origin of the broad shoulder in the vibrational spectra of hydrogen cycled Ti-doped NaAlH4 reported in a recent study.