TY - JOUR
T1 - ‘Ring-current’ and ‘pseudo-contact’ magnetic shielding by non-spherical molecules
JF - Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences
JO - Proc R Soc Lond A Math Phys Sci
SP - 209
LP - 225
M3 - 10.1098/rspa.1975.0173
VL - 346
IS - 1645
AU -
Y1 - 1975/10/28
UR - http://rspa.royalsocietypublishing.org/content/346/1645/209.abstract
N2 - A multipolar susceptibility formalism for interpreting and mapping the isotropic magnetic shielding outside axially symmetric molecules is con¬structed. The method involves spheroidal harmonic expansions of the local magnetic fields outside molecules magnetized by the uniform magneto¬ static field of the nuclear magnetic resonance spectroscopy experiment. For ‘disk-shaped’ molecules with infinite axial symmetry the shielding at field points with oblate spheroidal coordinates (U, V, Ø) reduces to where the coefficient aL0 measure anisotropy in the molecular susceptibilities and the PL(V) and QL(iU) are Legendre polynomials of the first and second kind. A similar result holds for prolate molecules like acetylene with cylindrical symmetry but additional terms appear for molecules like benzene with finite axial symmetry. The spheroidal expansions lead to more accurate descriptions of magnetic shielding outside non-spherical molecules than methods already available and are designed for interpreting experimental shieldings by both paramagnetic and diamagnetic molecules.
ER -