The oscillatory structure extending for hundreds of electron volts past the edges was called the “Kronig structure” after the scientist, Ralph Kronig, who assigned this structure in the high energy range ( i.e., for a kinetic energy range - larger than 100 eV - of the phoelectron in the weak scattering regime) to the single scattering of the excited photoelectron by neighbouring atoms in molecules and condensed matter.[10][11][12][13][14] This regime was called EXAFS in 1971 by Sayers, Stern and Little. [15] [16] and it developed only after the use of intense synctrotron radiation sources.