A single electron ion M(Z-1)+ with atomic number Z<84 emits a photon during an unknown electronic transition from some initial state ni to some final state nf. The photon then strikes an osmium surface, which has a work function = 5.93 eV and causes an electron to be emitted. Many such photons create a beam of electrons (all with the same kinetic energy) that is directed at a single crystal nickel sample at normal incidence. The electrons are scattered from the crystal and it is observed that they do so with only two (2) non-zero diffraction angles (i.e., 2 different values of q). From the DeBroglie-Bragg relation it is determined that the diffraction corresponds to a lattice spacing of a = 352.4 pm. E D F B A G a = lattice spacing E B

A single electron ion M(Z-1)+ with atomic number Z<84 emits a photon during an unknown electronic transition from some initial state ni to some final state nf. The photon then strikes an osmium surface, which has a work function = 5.93 eV and causes an electron to be emitted. Many such photons create a beam of electrons (all with the same kinetic energy) that is directed at a single crystal nickel sample at normal incidence. The electrons are scattered from the crystal and it is observed that they do so with only two (2) non-zero diffraction angles (i.e., 2 different values of q). From the DeBroglie-Bragg relation it is determined that the diffraction corresponds to a lattice spacing of a = 352.4 pm. E D F B A G a = lattice spacing E B