The effect of correlation on the surface potential of a free electron metal

Abstract

<dm:abstracts xmlns:dm="http://www.elsevier.com/xml/dm/dtd"><ce:abstract xmlns:ce="http://www.elsevier.com/xml/common/dtd" view="all" class="author" id="aep-abstract-id21"><ce:section-title>Publisher Summary</ce:section-title><ce:abstract-sec view="all" id="aep-abstract-sec-id22"><ce:simple-para id="fsabs010" view="all">This chapter discusses the effects of paramagnetism on nuclear magnetic resonances (NMR) of the ligand molecules by using lanthanide induced shift (LIS). Many lanthanide shift reagents are now available commercially, which are soluble in common organic solvents. Most of the reagents are lanthanide complexes of β-diketones having the basic 2,4-pentanedione structure. Some common reagents are Pr(fod)<ce:inf loc="post">3</ce:inf>, Eu(tfa)<ce:inf loc="post">3</ce:inf>, Yb(hfa)<ce:inf loc="post">3</ce:inf> and associated permutations. The shift reagents are tris-β-diketonates of lanthanides with a hexacoordinate structure and 3-fold symmetry axis. Nuclei of ligands in paramagnetic complexes are coupled to the electronic spin of the central ion by the electron-nuclear hyperfine interaction. As a result of this interaction, large chemical shifts in the NMR spectra of the ligands are observed. There are two independent mechanisms of hyperfine interaction: the contact interaction results from a finite probability of finding an unpaired electronic spin on an atomic s orbital, and the dipolar interaction takes place via space and causes shifts only if the magnetic susceptibility of the central ion is anisotropic.</ce:simple-para></ce:abstract-sec></ce:abstract></dm:abstracts>