Browsing by Author "Pogrebnoi, Alexander M."

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    Cluster ions in saturated vapor over barium difluoride: Structure and thermodynamic properties
    (Elsevier, 2016-07-16) Jacob, Fortunatus; Pogrebnoi, Alexander M.; Pogrebnaya, Tatiana P.
    Different cluster ions detected earlier in saturated vapor over barium fluoride have been studied here the oretically. The equilibrium geometrical parameters and vibrational spectra were obtained for the ions BaF3 , Ba2F3+, Ba3F5+, Ba4F7+, and Ba5F9+ . The DFT/B3P86 and MP2 methods were implemented with theTZVP basis sets including the diffuse and polarized basis functions. Along with cluster ions, the dimer molecule Ba2F4 properties were examined; the existence of isomeric forms was confirmed and the rela tive concentration of the isomers was evaluated. The enthalpies of ion molecular reactions were obtained both theoretically and based on experimental data. The enthalpies of formation DfHo(0) of the specieswere determined (in kJ mol 1): 1356 ± 4 (BaF3 ); 1039 ± 12 (Ba2F3+); 2179 ± 16 (Ba3F5+); 3277 ± 35(Ba4F7+); 4316 ± 22 (Ba5F9+); 1859 ± 7 (Ba2F4).
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    Ionic species in vapour over barium diiodide: Quantum chemical study of structure and thermodynamic properties
    (Elsevier, 2017-08-22) Jacob, Fortunatus; Pogrebnaya, Tatiana P.; Pogrebnoi, Alexander M.
    The 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 + ).
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    Structure and thermodynamic properties of cluster ions in saturated vapour over barium dibromide
    (Elsevier, 2016-12-27) Jacob, Fortunatus; Pogrebnaya, Tatiana P.; Pogrebnoi, Alexander M.
    The structure and thermodynamic properties of cluster ions detected earlier in saturated vapour over barium dibromide were studied theoretically. The equilibrium geometrical parameters and vibrational spectra were computed for the ions BaBr3 , Ba2Br3 + , Ba3Br5 + , Ba4Br7 + and Ba5Br9 + ; the DFT and MP2 methods with triple-zeta valence basis sets were used. The enthalpies of ion molecular reactions were obtained both theoretically through the total energies of participants and based on experimental data. The theo retical results were scrutinized with respect to methods of computation (DFT, MP2, and MP4). The enthalpies of formation DfHo (0) of the ions have been determined (in kJ mol 1 ): 858 ± 6 (BaBr3 ); 293 ± 10 (Ba2Br3 + ); 982 ± 20 (Ba3Br5 + ); 1644 ± 30 (Ba4Br7 + ); 2282 ± 17 (Ba5Br9 + ).