MOLECULAR STRUCTURE OF ErCl3 AND YbCl3 ACCORDING TO THE DATA OF THE SIMULTANEOUS ELECTRON DIFFRACTION AND MASS SPECTROMETRIC EXPERIMENT
N. I. Giricheva, S. A. Shlykov, G. V. Girichev, E. V. Chernova, E. A. Lapykina
Keywords: gas-phase electron diffractometry, mass spectrometry, erbium trichloride, ytterbium trichloride, vapor composition, molecular structure, vibration frequencies, quantum-chemical calculations, anharmonicity of vibrations
Pages: 251-261
Abstract
The saturated vapors of ErCl3 and YbCl3 were studied in a simultaneous electron diffraction and mass spectrometric experiment at 1165 K and 1170 K, respectively. In the vapors of these compounds, we found up to 3 mol.% dimers along with the monomers. The parameters of the rg effective configuration of the monomer molecules were determined. For ErCl3 and YbCl3, the internuclear distances rg(Ln-Cl) were 2.436(5) Å and 2.416(5) Å, and the bond angles ∠g(Cl-Ln-Cl) were 117.0(10)° and 117.2(10)°, respectively. The equilibrium configurations and vibration frequencies of the monomer and dimer molecules were calculated by the HF, B3LYP, and МР2 methods using the combination of the ECPD energy-consistent quasirelativistic core potential, including 4f electrons [Kr4d104fn], and the contracted [5s4p3d] valence basis set for Er and Yb atoms and the MIDIX [4s3p1d] basis set for Cl atoms. The parameters of the effective rg configuration of the monomer molecules corresponding to the temperature of the experiment were calculated. The difference between the calculated equilibrium rе(Ln-Cl) and temperature-averaged rg(Ln-Cl) distances was found to be 0.001-0.002 Å and did not exceed the error of the rg(Ln-Cl) parameter determined in the electron diffraction experiment. The experimental parameters of the rg structure were shown to be consistent with the idea about the planar equilibrium geometrical configuration of ErCl3 and YbCl3 molecules.
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