Luminescence spectroscopy of atomic zinc in solid rare gases. II. Temperature dependence

The temperature dependence of the pairs of emission bands present for atomic zinc isolated in annealed solid argon, krypton, and xenon samples is examined in steady-state and time-resolved luminescence spectroscopy. The pairs of emission bands in all the Zn/RG systems exhibited a reversible temperature dependence whereby the intensity of the high-energy band decreased, while the low-energy band gained in intensity with increasing temperature. In the Zn/Ar system, the decrease in the intensity of the 218.9 nm emission band observed between 9 and 28 K was coupled with a concomitant increase in the intensity of the band at 238 nm. In this temperature range the decay times of the 218.9 nm band decreased while the 238 nm band exhibited a constant decay time of 1.41 ns and a rise time correlated with the decay of the 218.9 nm band. The interdependence exhibited by the intensities and decay times of the two emission bands is modeled by an activated nonradiative process with a barrier height of 130.6 cm−1 for population interconversion between the pairs of emitting levels on of the spin singlet adiabatic potential energy surface. Similar behavior was observed in Zn/Kr between 6.3 to 20 K, but at higher temperatures this system also exhibited enhanced intersystem crossing. Likewise, for Zn/Xe, the low-energy 399 nm emission increased in intensity at the expense of the high-energy 356 nm emission up to a temperature of 40 K. For the Zn/Kr pair of singlet emissions and the Zn/Xe pair of triplet emissions, barrier heights of 78.1 and 42.6 cm−1 were evaluated, respectively