The relationship between the inner-shell electron energy-loss spectra and the 29Si NMR spectra of the chlorosilanes, SiHxCl4−x. An interpretation of the trend in NMR shieldings
✍ Scribed by J.A. Tossell
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 887 KB
- Volume
- 219
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
We have calculated the 29Si NMR shielding for the chlorosilanes, SiHXC14_X, using both the coupled Hartree-Fock method and the random phase approximation localized-orbital local-origins method, obtaining trends in good agreement with experiment for the first part of the series. Calculated inner-shell electron energy-loss spectra show a substantial stabilization of the LUMO between SiH4 and SiHsCl. Analysis of the paramagnetic part of the shielding in SiHsCl shows a large contribution from the HOMO, which is of predominant Cl 3p I[: type but with a significant Si-H a+ contribution. This orbital interacts with the LUMO of predominant Si-Cl a' type, in the presence of the magnetic field, strongly deshielding the Si.