Excitation and luminescence spectra of dipotassium hexafluoromanganate(IV)

Abstract

Measurement of the excitation and luminescence spectra of the salt K₂[MnF₆] prepared by different methods shows that the intense emission observed at low temperatures between 14 700 and 13 500 cm^–1 is caused by a Mn^IV species present as impurity. The ²E state of the impurity is populated by energy transfer from the ²E state of the [MnF₆]^2– ion thereby almost quenching the emission from the latter. The nature of this impurity is discussed. The previously reported absorption band at 19 300 cm^–1 is not present in the excitation spectrum and is attributed to another impurity. All the expected electronic and vibronic origins of the ⁴A₂→²E and ⁴A₂→²T₁ transitions of the [MnF₆]^2– ion have been identified.