LUMINESCENCE SPECTROSCOPY OF ATOMIC ZINC IN SOLID RARE-GASES .2. TEMPERATURE-DEPENDENCE

The temperature dependence of the pairs of emission bands present for atomic zinc isolated in annealed solid argon, krypton, and xenon sampl es is examined in steady-state and time-resolved luminescence spectros copy. The pairs of emission bands in all the Zn/RG systems exhibited a reversible temperature dependence whereby the intensity of the high-e nergy band decreased, while the low-energy band gained in intensity wi th increasing temperature. In the Zn/Ar system, the decrease in the in tensity 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 23 8 nm. In this temperature range the decay times of the 218.9 nm band d ecreased 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. Th e interdependence exhibited by the intensities and decay times of the two emission bands is modeled by an activated nonradiative process wit h a barrier height of 130.6 cm(-1) for population interconversion betw een the pairs of emitting levels on of the spin singlet adiabatic pote ntial energy surface. Similar behavior was observed in Zn/Kr between 6 .3 to 20 K, but at higher temperatures this system also exhibited enha nced 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 tripler emissions, barrier heights of 78.1 and 42.6 cm(-1) were evaluated, respectively. (C) 1997 American Institute of Physics.