Picture of Bonding in Protonated Phosphorus and Arsenic Clusters. Detection of 3-Center Bonds from the Generalized Population Analysis

In this report we provide a theoretical support for the existence of nonclassical 3-center bonding recently invoked to explain the structure of protonated phosphorus and arsenic X4H+ clusters.For this purpose the electron structure of these clusters was analysed using the formalism of the generalized population analysis, in terms of which the eventual presence of multicenter bonds in a mo-lecule can be directly detected and localized. Our results confirm the presence of 3-center bonding involving X−H−X fragments in these clusters