 The NOE is particularly important in the assignment of NMR resonances, and the elucidation and confirmation of the structures or configurations of organic and biological molecules.The two-dimensional NOE experiment (NOESY) is an important tool to identify stereochemistry of proteins and other biomolecules in solution, whereas in solid form crystal x-ray diffraction must be used to identify the stereochemistry.The NOE developed from the theoretical work of American physicist Albert Overhauser who in 1953 proposed that "nuclear" spin polarization could be enhanced by the microwave irradiation of the conduction "electrons" in certain metals.