The weak field representation of the crystal field matrices of d4,6 ions and the electronic absorption spectrum of RbFeF3

Abstract

The electronic absorption spectrum of RbFeF3 is reported and analysed by means of crystal field theory. It is shown that the strong field formalism is limited for high spin Fe2+ and the weak field representation should be used to interpret the many triplet states. Published spin-orbit weak field matrices for d4,6 are shown to contain errors. The weak field matrices in the absence of spin-orbit coupling have been derived and they are used to assign the spectrum of RbFeF3.