Vibronic transitions in the luminescence spectrum of Cs2NaEuCl6

The luminescence spectrum of Cs2NaEuCl6 has been measured at temperatures down to 5 K. Twenty-one electronic transitions between the 5 D 0, 5 D 1 and 5 D 2 excited states and ten of the crystal field states derived from the 7 FJ have been analysed. Overlapping transitions involving different excited states are distinguished by time resolved spectroscopy. Vibronic origins involving vibrational modes of about 80, 102, 240 and 250 cm-1 are prominent and are attributed to the v 6, v 4, v 3(TO) and v 3(LO) modes of the EuCl6 3- complex ion. This contrasts with a previous assignment.