Energy Spectrum of Mn⁺⁺ Ion in Calcium Fluorophosphate I

In order to find the effect of the change in the lattice constants of the host crystal upon the energy levels of the activator ion, calculations were performed for the particular case of calcium fluorophosphate activated by Mn ++ . The wave functions of the d 5 configuration in excited states are formed by the method of Condon and Shortley, and the matrix elements of the crystalline field potential at the Mn ++ ion were calculated. The Hamiltonian matrix thus obtained was diagonalized by a computer to derive the eigenvalues. On the assumption that the emission of this fluorescent body is due to the transition of Mn ++ ions from the lowest excited state to the ground state, the calculation leads to a shift of the emission peak by about 200Å to the longer wave length side caused by 1% decrease in the lattice constant.