Vibronic intensities in the electroni c spectra of transition metal complex ions. part IX. experimental study of the relative vibronic intensities in the2Eg →4A2g transition of the mnf2-6 ion in Cs2SiF6

Abstract

The relative intensities of about 90 of the more prominent vibronic bands in the2Eg →4A2g luminescence spectrum of the MnF2-6 ion in Cs2SiF6 have been measured at 80 K. The reported intensities cover a range of more than 106. Corrected values of the important intensity ratios of the v3, v4, v6 vibronic origins are given as 1:4 02:5-45. Most of the features can be assigned as progressions in the v1, v2 even parity vibrational modes based on the magnetic dipole allowed electronic origin and the v3, v4, v6 odd parity vibronic origins, up to four members of the progressions being observed. Prominent features also include combinations of the three odd vibrational modes. Anharmonic effects are small. The intensity mechanisms of these features are briefly discussed. It is likely that second order and third order Herzberg-Teller vibronic coupling makes a significant contribution to the intensity mechanism. These data will be used in subsequent theoretical models of the intensity mechanism. © 1