Rare gas-iodine complexes in the ion-pair states

Luminescence and luminescence excitation spectra in the vicinity of the optical-optical double resonance transitions to the I2(f0g+, vf = 8 and 9, Jf ≈ 55) levels have been measured at the bulb conditions for the I2 + Rg mixtures (Rg = He, Ar, Xe) at the rare gas pressures 2-20 Torr and room temperature. Luminescence attributed to the RgI2 complexes in the f0g+,F0u+andE0g+ ion-pair states has been observed for the first time. It is argued that the complexes can be formed by direct optical excitation from the RgI2(B0u+) complexes or {Rg+I2(B0u+)} colliding pairs. Besides, the RgI2 complexes in the f0g+,F0u+andE0g+ ion-pair states can be formed in nonadiabatic internal conversion processes from the RgI2(f0g+) one. The complexes have rather long lifetime, especially in the case of Xe, and decay radiatively and nonradiatively forming I2 molecules in different ion-pair states.