d-orbital theory for Mn 2+ -complex ions in crystals

The work is concerned with an ab initio calculation of the energy levels of Mn 2+ ions in MnF 2 . The essential idea is the application of an analytic approximation of Watson's SCF procedure to obtain the spin-orbit interaction and the electrostatic parameters for the isolated ions. Crystal field energy levels are then calculated using the nearest-neighbour point-ion approximation. Despite these approximations the results are quite good and indicate that the technique may be of general use as the starting point of more sophisticated calculations on the d n ion in crystals. In addition, the bands at 39010 cm -1 , 41340 cm -1 and 43200 cm -1 are interpreted in terms of double exciton transitions, which are in good agreement with experimental findings.