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

Abstract

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 Ϫ1 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 Ϫ1 were evaluated, respectively.

A pair potentials study of matrix-isolated atomic zinc. I. Excited 1P1 state dynamics in solid Ar

“…From an Arrhenius plot of the nonradiative rates extracted in the Zn-Ar kinetics study 11 it was shown that this process involved a barrier of 130.6 cm Ϫ1 . The origin of the temperature dependent interconversion of the two bands at higher temperatures will also be examined from the calculated excited-state potentials.…”

“…2 for an annealed sample at 9 K. Excitation into the 4p 1 P 1 -4s 1 S 0 absorption band, indicated by A in Fig. 2, produces the pair of emission bands at 219 and 238 nm labeled B and C. From lifetime measurements 10 The previously mentioned kinetics study 11 provided a wealth of information on the dynamics occurring on the excited 1 P 1 state surface of atomic zinc isolated in solid Ar. Thus on closer scrutiny of the temporal decay characteristics of the 238 nm emission it was noticed 11 that a risetime component, on the order of 0.1 ns, was present at low temperatures, TϽ13 K. Evidence for the existence of this risetime in the temporal decay profile of the C emission band is presented in Fig.…”

“…From an analysis of the kinetics 11 it can be concluded, because of the presence of a risetime on the C emission band …”

“…8 are extended to check their efficacy in predicting the temperature dependence observed in a previously published kinetic study 11 of the luminescence in the Zn-Ar system. A summary of the luminescence spectroscopy in the Zn-Ar system is presented in Fig.…”

A pair potentials study of matrix-isolated atomic zinc. II. Intersystem crossing in rare-gas clusters and matrices

“…In starker contrast to the Zn-Ar system, there is also a triplet emission band at 312 nm in Zn-Kr, the intensity of which is temperature dependent. 2 Excitation into the singlet 4p 1 P 1 ←4s 1 S 0 absorption band of Zn-Xe produces no spin singlet emission at all, with emission occurring only as the pair of spin triplet bands at 356 and 399 nm.…”