Emission Spectra of Deep Impurity States in Solid and Liquid Rare Gas Alloys

We have measured the spectral distribution (in the region 1100–2000 Å) of the α excited luminescence from solid and liquid dilute rare gas alloys. Emission was observed from the lowest deep impurity state of xenon in liquid and in solid argon, which provides evidence for medium relaxation resulting in a ``cavity'' formation around the excited impurity in dense rare gases.