Pseudo-Zeeman splitting of excited states in MnI2: Cu+

MnI₂ doped with CuI shows extra absorption lines in the spectral region between 24000 and 30000 cm^-1. At low temperature these lines have an anomalously large Zeeman splitting in an applied magnetic field, with apparent g values as large as 150. This effect is attributed to exchange coupling of an electron (or hole) in the excited state with the spins of the surrounding Mn²⁺ ions. The applied magnetic field partly aligns the Mn²⁺ ion spins and this causes the observed very large pseudo-Zeeman splitting of the absorption lines.