THE ANALYSIS OF MOLECULAR WAVE FUNCTIONS BY NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY

A valence-bond formulation is presented for the relationship between molecular wave functions and the electron-coupled nuclear spin interactions observed by nuclear magnetic resonance spectroscopy. For non-bonded atoms, the magnitude of the coupling is shown to depend on the deviations from perfect pairing in the wave function. This result makes it possible to use the measured coupling constants in testing models for hyperconjugation. An application to the second-order hyperconjugation in ethane is given. For directly-bonded atoms, the coupling constant depends on parameters, such as orbital hybridization and bond polarization, in localized electron-pair functions. Use of this dependence is made to determine the bond polarization in several tetrahedral molecules.