Electronic properties of the Fe2+ ion in CaF2 from Mössbauer and far infrared spectroscopy

2014 The system CaF2 : Fe2+ has been studied by Mössbauer spectroscopy in the slow relaxation regime (4.2-14 K). Far infrared experiments have been performed in the 1.5-35 K temperature range and at 1.5 K in an external magnetic field up to 8 T. From both Mössbauer and far infrared results, one can deduce that the average distance between the spin-orbit levels within the Eg state is K = 17 cm-1. This value lies in the typical range 10-20 cm-1 predicted by Ham. From this measure of K, we propose for the distance 0394 between the Eg and T2g orbital states the calculated value 0394 = 5 320 cm-1. We conclude that crystal field theory alone can account for the electronic properties of the 5Eg ground state and consequently dynamical Jahn-Teller effects can be neglected. LE JOURNAL DE PHYSIQUE TOME 40, OCTOBRE 1979,