Unusually Large Change in Radiative Lifetime of the $A$-Band Emission in KI: ${\mathrm{In}}^{+}$ and KI: ${\mathrm{Sn}}^{2+}$ Induced by a Magnetic Field

We have studied the magnetic field dependence of the decay time of the emission in KI: ${\mathrm{In}}^{+}$ and KI: ${\mathrm{Sn}}^{2+}$ produced at low temperatures by $A$-band excitation. The decay time decreases by almost 2 orders of magnitude in a field of 46 kG. This unusually large decrease has been correlated with the mixing due to the magnetic field among the excited states $\left|{\hat{A}}_{1\mathrm{u}}\right({{\Gamma }_1}^{-})〉$, $\left|{\hat{A}}_{2\mathrm{u}}\right({{\Gamma }_4}^{-})〉$, and $\left|{\hat{E}}_{\mathrm{u}}\right({{\Gamma }_4}^{-})〉$, which are distorted tetragonally by the Jahn-Teller effect.