Metal atom (Zn, Cd and Mg) luminescence in solid neon

Abstract

Luminescence spectroscopy of the metal atoms Mg, Zn and Cd isolated in solid neon is recorded using pulsed synchrotron radiation excitation of the ns 1 np 1 1 P 1 -ns 2 1 S 0 resonance (n = 3, 4 and 5 respectively) transitions. Two features, a dominant band and a red-shoulder, are identified in the UV absorption spectra of Zn/Ne and Cd/Ne. Excitation of these features yields distinct emission bands with the red-shoulder absorption producing the smaller, Stokes-shifted emission. Nanosecond decaytime measurements, made with the time correlated single photon counting technique indicate the emission bands arise from the spin singlet 1 P 1 → 1 S 0 transition. Hence, it is concluded the duplication of absorption and emission features in the Cd/Ne and Zn/Ne systems arises from metal atom occupancy in two distinct sites. In contrast, Mg/Ne luminescence consists of single excitation and emission bands, indicative of occupancy in just one site. The occurrence of distinct photophysical characteristics of the linewidths, Stokes shift and lifetimes in the Mg/Ne system, compared with those recorded for Zn/Ne and Cd/Ne, is rationalised in terms of a different site occupancy for atomic Mg. Accurate interaction potentials for the ground states of the M·Ne diatomics are used to analyse site occupancies and interpret this contrasting behavior.

Vacuum Ultraviolet Spectroscopy and Photochemistry of Zinc Dihydride and Related Molecules in Low-Temperature Matrices

“…However, it also exhibits characteristic 3-fold splitting, with partially resolved features at 212.6, 214.5, and 216.5 nm. For comparison purposes, the absorption spectrum of atomic zinc isolated in solid neon 11 is shown by the bottom trace in Figure 1. While the atomic band in neon is located blue of the gas phase transitionroughly in the same region as Zn/D 2 3-fold splitting is not evident and additional bands due to Zn dimer are now present at the indicated positions.…”

“…With a radiative lifetime of 1.16 ns and its spectral location, these characteristics indicate that this emission can be assigned to the fully allowed 4p 1 P 1 → 4s 1 S 0 transition. Thus, singlet P-state fluorescence dominates in neon, 11 as it does in argon and krypton matrices. 12 In light of the data presented in Figure 2, it is thereby evident that singlet fluorescence of atomic zinc is completely quenched in both solid D 2 and CH 4 .…”

“…Moreover, the proposal of this site occupancy is consistent with the much more efficient isolation of atomic zinc in solid D 2 than in solid neon as revealed in the absorption spectra shown in Figure 1. Multivacancy occupancy has been proposed 11 for the site of isolation of atomic zinc in solid neon.…”

Theoretical study of “trapping sites” in cryogenic rare gas solids doped with β-dicarbonyl molecules

“…Site effects play an important role in the spectroscopy of atomic and molecular impurities trapped in cryogenic solids [1][2][3][4][5][6][7][8][9]. Their influence is connected with the observation for a single vibrational mode or a single vibronic transition, of several bands in absorption and emission and with the shapes of the bands [1][2][3]10]. In presence of different trapping sites it is a difficult task to separate the individual spectroscopic contribution of each site.…”

“…In presence of different trapping sites it is a difficult task to separate the individual spectroscopic contribution of each site. Several experimental and theoretical methods have been developed and used for this purpose [1][2][3][4][5][6][7][8][9][10]. Among them, molecular dynamics (MD) represents an useful tool to describe cryogenic crystals.…”