Spin Characterization of Lanthanoid Ion Eu2± (8S7/2) in a CaF2 Single Crystal by Electron Spin Transient Nutation Spectroscopy

One of lanthanoid ions, Eu2± (8S7/2), doped in a CaF2 single crystal with cubic symmetry has been studied by an Electron Spin Transient Nutation (ESTN) method of pulsed ESR spectros-copy. In a two-dimensional ESTN spectrum of the Eu2± ion, the nutation frequencies indicated the dependence of hyperfine ESR transitions as well as of spin quantum number S and MS manifolds. It is demonstrated that the 2D-ESTN method discriminates the hyperfine allowed ESR transitions from the hyperfine forbidden ones. Such discrimination of the ESR transitions enables us to make facile assignments of complicated ESR spectra. The nutation frequencies observed for the hyperfine allowed / forbidden transitions were quantitatively understood with the help of reduced rotation matrix elements.