Induced Magnetic Fields and NMR Parameters

In Section 5.4 it was discussed that the interaction of a charge distribution with an external magnetic induction, B, or with a nuclear magnetic moment, m, leads to an induced current density According to Eq. (5.49) this will also give rise to 

The product j R)B is the contribution to the induced electronic magnetic induction at point R coming from changes in the motion of the electrons due to an external magnetic induction, while the product K R) rh is the additional electronic magnetic induction induced by the magnetic moment and thus by the nuclear spin T.  

These definitions are aiso inciuded in Tabie B.2 of Appendix B. 

However, the shielding constant cannot be obtained from an NMR spectrum. The parameter actually measured is the chemical shift 5, which is the relative difference of the Larmor or resonance frequency of nucleus K and the Larmor frequency i/K,ref jjjg gajjjg nucleus in a reference molecule 

The Larmor or resonance frequency is the frequency of an allowed transition between two nuclear spin states of nucleus K. The energy of a nuclear spin state in 

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