Site-selected luminescence of atomic europium in the solid rare gases

Byrne, Owen; McCaffrey, John G.

doi:10.1063/1.3609116

Cited by 4 publications

(5 citation statements)

References 12 publications

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“…The data obtained by thermal deposition of Yb atoms by our group are compared to that obtained by ablation deposition techniques in previously published works. 10 The matrix-isolated Eu atom, which differs from the Yb atom in its 4f shell occupation (7 unpaired electrons vs. 14 paired ones), has been thoroughly investigated by Byrne and McCaffrey 8,9,37 and offers an interesting point of comparison. In solid Ar, Eu was found to occupy two stable trapping sites, "red" and "blue," with mean frequency shifts of 760 and 1350 cm −1 , respectively, in the 6s 2 8 S → 6s6p y 8 P transition.…”

Section: A Matrix Trapping Sitesmentioning

confidence: 99%

“…In comparison, studies of multiple site occupation by nonalkali atoms have been limited. To date, the only other species found to occupy pairs of thermally stable sites are Mn 6,7 and Eu 8,9 in solid Ar and Kr. Earlier work on another lanthanide in isolation, Yb, mentions that "absorption bands may be broadened and/or further split due to inhomogeneity of matrix sites."…”

Section: Introductionmentioning

confidence: 99%

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Heat- and light-induced transformations of Yb trapping sites in an Ar matrix

Tao

Kleshchina

Lambo

et al. 2015

The Journal of Chemical Physics

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The low-lying electronic states of Yb isolated in a solid Ar matrix grown at 4.2 K are characterized through absorption and emission spectroscopy. Yb atoms are found to occupy three distinct thermally stable trapping sites labeled "red," "blue," and "violet" according to the relative positions of the absorption features they produce. Classical simulations of the site structure and relative stability broadly reproduced the experimentally observed matrix-induced frequency shifts and thus identified the red, blue, and violet sites as due to respective single substitutional (ss), tetravacancy (Tv), and hexavacancy (Hv) occupation. Prolonged excitation of the (1)S → (1)P transition was found to transfer the Yb population from hv sites into Tv and ss sites. The process showed reversibility in that annealing to 24 K predominantly transferred the Tv population back into Hv sites. Population kinetics were used to deduce the effective rate parameters for the site transformation processes. Experimental observations indicate that the blue and violet sites lie close in energy, whereas the red one is much less stable. Classical simulations identify the blue site as the most stable one.

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Section: A Matrix Trapping Sitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Heat- and light-induced transformations of Yb trapping sites in an Ar matrix

Tao

Kleshchina

Lambo

et al. 2015

The Journal of Chemical Physics

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“…A brief luminescence study was performed to check the formation of standard samples with typical Eu/RG emission and excitation features. 2 Following this, samples underwent unfocussed dye laser irradiation of the y 8 P state for periods of 15-30 min at laser energies in the range 250-300 μJ/mm 2 . The dyes used to produce laser output at 465.5 nm (Xe), 451 nm (Kr), 450.1 nm (Ar, red site), and 438.3 nm (Ar, blue site) are specified below.…”

Section: A Experimentalmentioning

confidence: 99%

In situ formation and characterisation of singly ionised atomic europium in rare gas matrices—Luminescence spectroscopy and MP2 calculations

Byrne

Davis

McCaffrey

2015

The Journal of Chemical Physics

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Irradiation of atomic europium isolated in the solid rare gases, with low intensity laser excitation of the y 8 P ← a 8 S resonance transition at ca. 465 nm, is found to produce singly charged europium cations (Eu + ) in large amounts in xenon and in smaller amounts in argon. Confirmation of the formation of matrix-isolated Eu + is obtained from characteristic absorption bands in the UV and in the visible spectral regions. The luminescence produced with excitation of the cation bands is presented in greatest detail for Eu/Xe and assigned. Excitation of the 4f 7 ( 8 S 7/2 )6p 3/2 absorption bands of Eu + between 390 and 410 nm produces emission which is quite distinct from that resulting from excitation of the 4f 7 ( 8 S 7/2 )6p 1/2 absorption (430 to 450 nm) features. The latter consists of narrow, resolved emission bands with Stokes shifts ten times smaller than the former. The observed spectral differences are discussed in relation to the different spatial symmetries of the p 3/2 and p 1/2 orbitals in these j-j coupled (7/2, 3/2) J and the (7/2, 1/2) J levels. Møller-Plesset calculations are conducted to obtain the molecular parameters of the neutral Eu-RG and cationic Eu (2011)], the interaction potentials calculated herein for the Eu-RG diatomics suggest that the neutral Eu atom occupies tetra-vacancy (tv) and hexa-vacancy (hv) sites in the solid rare gas hosts. Possible reasons for the facile production of Eu + in the solid rare gases are discussed. The mechanism proposed is that atomic europium is also acting as an electron acceptor, providing a temporary trap for the ionised electron in the matrices. C 2015 AIP Publishing LLC. [http://dx

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“…With the same (single vacancy) site occupied in these M/RG systems, a linear dependence of matrix shift with host polarizability is observed. This behavior was also found for atomic Na, Mn, and Eu even though considerable guest/host size mismatches exist, resulting in more complex absorption profiles from the occupancy of these guest atoms in multiple sites. In these cases, polarizability plots allowed for associations to be made for the same site types occupied by metal atoms in the three rare gas solids.…”

Section: Introductionmentioning

confidence: 59%

“…Based on absorption data, it was proposed by us in an earlier paper that three thermally stable sites of isolation exist for Ba in solid Ar and Kr and at least two sites occur in Xe. This analysis assumed the occurrence of a Jahn–Teller threefold split band for each matrix site, as was the case for the other spherically symmetric M/RG systems studied by the Maynooth Group. , However, the present analysis of the (6s6p) 1 P 1 ↔ (6s 2 ) 1 S 0 luminescence of Ba isolated in the three RG solids (Ar, Kr, and Xe) reveals a more complex situation. Excitation spectroscopy was particularly useful in revealing bands severely overlapped in the absorption spectra, the details of which will now be presented.…”

Section: Introductionmentioning

confidence: 83%

Luminescence of Atomic Barium in Rare Gas Matrices: A Two-Dimensional Excitation/Emission Spectroscopy Study

Davis

McCaffrey

2018

J. Phys. Chem. A

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A detailed characterization is made of the distinct sites occupied by atomic barium isolated in the three rare gas hosts Ar, Kr, and Xe in excitation scans extracted from the recorded total 6s6p P → (6s)S fluorescence. Extensive use has been made of two-dimensional excitation/emission (2D-EE) spectroscopy to achieve a comprehensive characterization for the wide variety of sites present in the Ba/RG matrix systems. The 2D-EE technique has proved to be a very powerful method to probe the effects of strong intersite reabsorption when extensive spectral overlap occurs between emission and resonance 6s6p P ← (6s)S absorption of barium atoms occupying multiple sites. Two-dimensional excitation/emission scans have also been used in this study to monitor the effects of sample annealing and thereby identify the thermally stable sites of isolation. Sites of the same type occupied by atomic barium in the three host solids are identified in resolved excitation spectra and are associated on the basis of the observed matrix shift versus host polarizability. Following site associations, the photophysical properties of each matrix site were characterized revealing that the Stokes shift was greatest in the blue site, smallest for the violet site, and intermediate for the green site. The emission temperature dependences and excited state lifetimes were recorded, indicating that measured radiative lifetimes of 4-5 ns were in good agreement with the gas phase value of 8.4 ns when corrected for the effective field of the solids. The only exception to this was the blue site in Ba/Xe, where a nonradiative quenching channel exists even at 9.8 K that competes effectively with the nanosecond fluorescence. An unusual, asymmetric 2 + 1 excitation band has been recorded for atomic barium in the three rare gas hosts in addition to the threefold split, Jahn-Teller bands typically observed for P ← S absorptions of matrix-isolated metal atoms. Possible assignments of the sites responsible for these band shapes are made on the basis of recent spectral simulations obtained from molecular dynamics calculations on the Ba/Xe system.

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Site-selected luminescence of atomic europium in the solid rare gases

Cited by 4 publications

References 12 publications

Heat- and light-induced transformations of Yb trapping sites in an Ar matrix

Heat- and light-induced transformations of Yb trapping sites in an Ar matrix

In situ formation and characterisation of singly ionised atomic europium in rare gas matrices—Luminescence spectroscopy and MP2 calculations

Luminescence of Atomic Barium in Rare Gas Matrices: A Two-Dimensional Excitation/Emission Spectroscopy Study

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