Geometrical and electronic structure of LaI3 molecule from the gas electron diffraction data and quantum chemical calculations |
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Authors: | N. I. Giricheva S. A. Shlykov G. V. Girichev I. E. Galanin |
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Affiliation: | (1) Ivanovo State University, Russia;(2) Ivanovo State University of Chemical Technology, Russia |
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Abstract: | The saturated vapor over LaI3 has been studied using the electron diffraction method with mass-spectral monitoring. It was determined that at a temperature 1142(10) K, along with monomer molecules, dimers are present in the vapor in the quantity of 0.7 mol.%. Effective configuration parameters of LaI3 molecule were obtained: r g(La-I) 2.961(6) Å, ∠g(I-La-I) 116.5(9)°, l(La-I) 0.106(1) Å and l(I…I) 0.412(7) Å. A small deviation of the valence angle ∠g(I-L-I) from 120° can be totally caused by a contraction effect of the distance r g(I…I) of LaI3 molecule with planar equilibrium configuration. The electronic structure of LaI3 molecule was examined by the B3LYP/SDD method. In terms of the NBO-analysis, the participation of lanthanum 4f-AO in bonding orbitals La-I is noted. It is shown that the NBO-analysis describes the bond La-I in LaI3 molecule as predominantly ionic one with a noticeable covalence component. The energy of the heterolytic bond breakage E(La-I)het = 1216 kJ/mole was calculated. |
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Keywords: | gas electron diffraction mass-spectrometry quantum chemistry lanthanum triiodide molecular structure vibration frequencies |
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