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Shielding Effects in Covalent Halogen Compounds

Conference paper
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Part of the NMR Basic Principles and Progress Grundlagen und Fortschritte book series (NMR, volume 12)

Abstract

Let us consider a molecule fixed in space and containing a magnetic nucleus. If the molecule is exposed to a uniform static magnetic field \( {\bar B_O} \) this will act on the electrons to induce a small additional field \( \mathop {\rm{B}}\limits^{\rm{\_}} \prime \). At the position of our magnetic nucleus the local field, \( {{\bar B}_{loc}} \), will be
$$ {{\bar B}_{loc}} = {\bar B_O}{\rm{ + }}\mathop {\rm{B}}\limits^{\rm{\_}} \prime $$
(3.1)
Experimental evidence as well as theoretical arguments indicate that for reasonably moderate magnetic fields (cf. discussion by Ramsay [143]) the induced field is proportional to \( {\bar B_O} \) but not necessarily aligned parallel to it and one may write
$$ \mathop {\rm{B}}\limits^{\rm{\_}} \prime {\rm{ = - \tilde \sigma }}{\bar B_O} $$
(3.2)
where \( {\rm{\tilde \sigma }} \) is a second rank tensor — the nuclear shielding tensor.

Keywords

Atomic Orbital Valence Shell Quadrupole Coupling Constant Alkali Halide Crystal Paramagnetic Contribution 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1976

Authors and Affiliations

  1. 1.Department of Physical Chemistry Chemical CentreUniversity of LundLundSweden

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