Symmetry andgvalue of the relaxed excited state of KI:TI+AXemission

Abstract

We report the effect of a magnetic field applied along the $〈111〉$ and $〈100〉$ directions on the luminescent decay time of the ${A}_{X}$ emission of KI:T${\mathrm{I}}^{+}$. From the directional dependence we show that the ${A}_{X}$ emission arises from a trigonal Jahn-Teller (JT) well. The field dependence of the decay time also provides an estimate of the $g$ value of the emitting state, which we find as $g\ensuremath{\sim}1$. This is shown to be consistent with the emitting state being a JT minimum on the $^{3}T_{1u}$ adiabatic potential-energy surface in the presence of strong spin-orbit interaction.