The results of measurements and analysis of excitation spectra of the λ lum =2350Ǻ luminescence corresponding to I 2 (D0 + u →X0 + g ) transition as well as luminescence at λ lum =3400Ǻ, where I 2 (D’2 g →A’2 u and/or β1 g →A1 u ) transitions occur, observed after three-step, λ 1 +λ f +λ 1 , λ 1 =5321–5508.2Ǻ, λ f =10644.0Ǻ, laser excitation of pure iodine vapour and I 2 +Xe mixtures at room temperature are presented. Luminescence spectra in the λ lum =2200–3500Ǻ spectral range are also analyzed. We discuss three alternative mechanisms of optical population of the IP states. In our opinion, the mechanism including the MI 2 , M=I 2 , Xe, complexes is the most probable at least in the λ 1 ≈5321–5480Ǻ, λ 1 ≈5508Ǻ spectral ranges and for population of the states which luminescence occur at λ lum ≈3400Ǻ.