High-resolution MCD spectroscopy of transition metal ions in fluoride crystals

Abstract

A brief description of a high-resolution circular dichrograph is given. For MCD measurements a 0·52 T permanent magnet and silica flow tubes are used to obtain data with variable sample temperatures as low as 4·2 K. The MCD results provide an unambiguous assignment of the ⁴ A _1g and ⁴ E_g ^a states of Mn²⁺ in KMgF₃ and KZnF₃. The ⁴ E_g ^a state lies 90–100 cm^-1 below ⁴ A _1g . A theoretical analysis of the MCD results confirms the assignment of the ⁴ A _1g state, while an analysis of the spin-orbit splitting of the ⁴ E_g ^a state has been carried out using all 252 |αLSJM_J > functions of the d⁵ configuration. The observed positions of the three components of ⁴ E_g ^a are accurately accounted for by Dq values appropriate to KMgF₃ and KZnF₃ and a spin-orbit coupling constant of approximately 300 cm^-1.