Theoretical prediction of rare gas inserted hydronium ions: HRgOH2+

A possibility of existence of new species through insertion of a rare gas atom in hydronium ion resulting into HRgOH2+ cation (Rg = He, Ar, Kr, and Xe) has been explored by using various ab initio quantum chemical techniques. Structure, harmonic vibrational frequencies, stability, and charge distribution of HRgOH2+ species as obtained using density functional theory, second order Møller-Plesset perturbation theory, and coupled-cluster theory based methods are reported in this work. All the calculated results suggest that the HRgOH2+ species are stable enough with respect to all the dissociation channels, except the 2-body dissociation path (H3O++ Rg). Nevertheless, this 2-body dissociation channel connected through the relevant transition state is associated with a finite barrier, which in turn would prevent the metastable species in transforming to global minimum products. The calculated values of topological properties within the framework of quantum theory of atoms-in-molecules are found to be consistent with the bond length values. Structural and energetic parameters clearly suggest that it might be possible to prepare and characterize the HRgOH2+ species (except HHeOH2+) using electron bombardment matrix isolation technique in a way similar to that of the preparation of (Rg2H)+ or mixed (RgHRg′)+ cations.