Jacob, FortunatusPogrebnaya, Tatiana P.Pogrebnoi, Alexander M.2024-06-172024-06-172017-08-22https://repository.udsm.ac.tz/handle/123456789/6080The cluster ions Ba2I3 + , Ba3I5 + and Ba4I7 + were detected earlier in saturated vapour over barium diiodide using high temperature mass spectrometric technique. In this work the structure and thermodynamic properties of the species BaI3 , Ba2I3 + , Ba3I5 + , Ba4I7 + , and Ba5I9 + have been studied theoretically by using the density functional theory (DFT/B3P86) and Møller–Plesset perturbation theory (MP2 and MP4) with triple-zeta valence basis sets. The enthalpies of ion molecular reactions have been determined both the oretically and based of available experimental data; the enthalpies of formation of the cluster ions are found as follows (in kJ mol 1 ): 709 ± 6, (BaI3 ), 96 ± 10 (Ba2I3 + ), 654 ± 15 (Ba3I5 + ), 1177 ± 20 (Ba4I7 + ) and 1686 ± 20 (Ba5I9 + ).enCluster ionsGeometrical structureVibrational spectraBarium diiodideEnthalpies of formationThermodynamic functionsDFTMP2 and MP4Journal Articlehttp://dx.doi.org/10.1016/j.comptc.2017.08.022