Theoretical investigation of HNgNH3+ ions (Ng = He, Ne, Ar, Kr, and Xe)

The equilibrium geometries, harmonic frequencies, and dissociation energies of HNgNH₃⁺ ions (Ng = He, Ne, Ar, Kr, and Xe) were investigated using the following method: Becke-3-parameter-Lee-Yang-Parr (B3LYP), Boese-Matrin for Kinetics (BMK), second-order Møller-Plesset perturbation theory (MP2), and coupled-cluster with single and double excitations as well as perturbative inclusion of triples (CCSD(T)). The results indicate that HHeNH₃⁺, HArNH₃⁺, HKrNH₃⁺, and HXeNH₃⁺ ions are metastable species that are protected from decomposition by high energy barriers, whereas the HNeNH₃⁺ ion is unstable because of its relatively small energy barrier for decomposition. The bonding nature of noble-gas atoms in HNgNH₃⁺ was also analyzed using the atoms in molecules approach, natural energy decomposition analysis, and natural bond orbital analysis.