Cluster ions in saturated vapor over barium difluoride: Structure and thermodynamic properties

摘要

Different cluster ions detected earlier in saturated vapor over barium fluoride have been studied here theoretically. The equilibrium geometrical parameters and vibrational spectra were obtained for the ions BaF3-, Ba2P3+, Ba3F5+, Ba4F7+, and Ba5F9+. The DFT/B3P86 and MP2 methods were implemented with the TZVP 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 relative 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 Delta H-f(o)(0) of the species were determined (in kJ mol(-1)): -1356 +/- 4 (BaF3-); -1039 +/- 12 (Ba2F3+); -2179 +/- 16 (Ba3F5+); -3277 +/- 35 (Ba4F7+); -4316 +/- 22 (Ba5F9+); -1859 +/- 7 (Ba2F4). (C) 2016 Elsevier B.V. All rights reserved.