Coupled cluster, MP2, and DFT study of structures, stabilities, vibrations, and bonding properties of XXeOH (X = F, Cl, Br, and I)

Abstract

The optimized geometries, molecular properties, and stabilities of new noble gas molecules, XXeOH (X = F, Cl, Br, and I), were studied using CCSD, MP2, CAM-B3LYP, and WB97XD methods and large basis sets. All XXeOH molecules showed equilibrium structures with Cs symmetry. The results also showed that some bonds in XXeOH could be presented as a typical ionic bond. An alteration in ion-pair character was observed for IXeOH, showing two OH− and IXe+ parts, while in other molecules, they could be presented as XeOH+ and X−. Two decomposition routes were proposed for these molecules that showed high exothermic reactions. However, despite their low thermodynamic stabilities, their decomposition rate constants were small and all molecules (except BrXeOH) had high kinetic stabilities, indicating the possibility for identification and characterization of these molecules. However, in addition to the calculation of their vibrational frequencies, NBO atomic charges, and hybridizations, the bonding properties of XXeOH molecules were studied by AIM calculations (to calculate electron densities, bond elipticities, and Laplacian of electron densities) and second-order intramolecular perturbation energies using NBO calculations. Moreover, the ease of formations and relative stabilities of XXeOH molecules were compared using heats of formations, Gibbs free energies of formations and isodesmic reactions. These calculations showed that the stability of XXeOH molecules was decreased from F to I.