Luminescence spectroscopy of atomic zinc in rare-gas solids. I

Low Temperature Physics

2012

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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.

Section: Introductionmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 99%

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

Healy

Kerins

Low Temperature Physics

2012

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“…Since the optical layout of the HIGITI apparatus located at HASYLAB/DESY in Hamburg has been presented in our earlier work, 3 only a brief description will be given here. Synchrotron radiation optimized in the VUV spectral region was used as the excitation source.…”

Section: Methodsmentioning

confidence: 99%

A synchrotron radiation study of high-lying excited states of matrix-isolated atomic magnesium

Kerins

Healy

Low Temperature Physics

2000

Previous steady-state and time-resolved luminescence spectroscopy of 3p 1 P 1 atomic magnesium, isolated in thin film samples of the solid rare gases, is extended to include the higher energy 4p 1 P 1 excitation. Well-resolved site splittings are recorded in Mg/Ar samples for excitation to the 4p 1 P 1 level. A small red shift in the absorption energy to the 4p 1 P 1 level for Mg/Ar contrasts with a small blue shift on absorption to the 3p 1 P 1 level. Direct emission from the 4p 1 P 1 level is not observed in any of the rare gas matrices; instead, intense emission from the low energy 3p 1 P 1 level is. Measurements of the emission decay curves in Mg/Ar have revealed slow rates in the steps feeding the 3p 1 P 1 level following 4p 1 P 1 excitation. The reason for the differential shifting of the 4p 1 P 1 and 3p 1 P 1 levels as well as the lack of direct 4p 1 P 1 emission is thought to be related to the strong binding interaction between Mg in the 4p 1 P 1 state and the rare gases.

“…Thus, d → s transitions are observed to be narrow and unshifted from their gas phase positions, while p → s transitions are now well known to be broad, exhibiting large Stokes-shifted emission. More recently, our group at Maynooth has looked at the luminescence of matrix-isolated atomic Zn, 8 Cd, 9 and Hg 10 and observed that the emission is dominated by P → S transitions. To date, no work has appeared on the luminescence of atomic Mn whose absorption 11 is also dominated by P ← S transitions.…”

Section: Introductionmentioning

confidence: 99%

Luminescence spectroscopy of matrix-isolated zP6 state atomic manganese

Collier

The Journal of Chemical Physics

2005

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The relaxation of electronically excited atomic manganese isolated in solid rare gas matrices is observed from recorded emission spectra, to be strongly site specific. z 6 P state excitation of Mn atoms isolated in the red absorption site in Ar and Kr produces narrow a 4 D and a 6 D state emissions while blue-site excitation produces z 6 P state fluorescence and broadened a 4 D and a 6 D emissions. Mn/ Xe exhibits only a single thermally stable site whose emission at 620 nm is similar to the broad a 6 D bands produced with blue-site excitation in Ar and Kr. Thus in Ar͑Kr͒, excitation of the red site at 393 ͑400͒ nm produces narrow line emissions at 427.5 ͑427.8͒ and 590 ͑585.7͒ nm. From their spectral positions, linewidths, and long decay times, these emission bands are assigned to the a 4 D 7/2 and a 6 D 9/2 states, respectively. Excitation of the blue site at 380 ͑385.5͒ nm produces broad emission at 413 ͑416͒ nm which, because of its nanosecond radiative lifetime, is assigned to resonance z 6 P → a 6 S fluorescence. Emission bands at 438 ͑440͒ and 625 ͑626.8͒ nm, also produced with blue-site excitation, are broader than their red-site equivalents at 427.5 and 590 nm ͑427.8 and 585.7 nm in Kr͒ but from their millisecond and microsecond decay times are assigned to the a 4 D and a 6 D states. The line features observed in high resolution scans of the red-site emission at 427.5 and 427.8 nm in Mn/ Ar and Mn/ Kr, respectively, have been analyzed with the W p optical line shape function and identified as resolved phonon structure originating from very weak ͑S = 0.4͒ electron-phonon coupling. The presence of considerable hot-phonon emission ͑even in 12 K spectra͒ and the existence of crystal field splittings of 35 and 45 cm −1 on the excited a 4 D 7/2 level in Ar and Kr matrices have been identified in W p line shape fits. The measured matrix lifetimes for the narrow red-site a 6 D state emissions ͑0.29 and 0.65 ms͒ in Ar and Kr are much shorter than the calculated ͑3 s͒ gas phase value. With the lifetime of the metastable a 6 D 9/2 state shortened by four orders of magnitude in the solid rare gases, it is clear that the probability of the "forbidden" a 6 D → a 6 S atomic transition is greatly enhanced in the solid state. A novel feature identified in the present work is the large width and shifted 4 D and 6 D emissions produced for Mn atoms isolated in the blue sites of Ar and Kr. In contrast, these states produce narrow, unshifted ͑gas-phase-like͒ 4 D and 6 D state emissions from the red site.