Optical absorption and Zeeman spectra of Cr3+dimers in Cs3Cr2Br9

Abstract

The spectrum of Cr3+ dimers in Cs3Cr2Br9 has been studied using high-resolution optical absorption and Zeeman spectroscopy in magnetic fields up to 13 T. In particular, a detailed investigation of transitions from the dimer ground manifold (4A2*4A2) to the singly-excited dimer manifold (4A2*2T1) has been made and the results are discussed in terms of a recently suggested approach to the problem of dimers of D3h symmetry. The experimental results reported are more detailed than those previously obtained by similar techniques on the chlorine isomorph and provide a more rigorous test of the theory. In addition, anomalously low g-values for the orbital singlet states detected by the Zeeman measurement are reported and the possible role of electron delocalisation is considered.