Davis, Barry and Gervais, Benoit and McCaffrey, John G.
(2018)
An investigation of the sites occupied by
atomic barium in solid xenon—A 2D-EE
luminescence spectroscopy and molecular
dynamics study.
Journal of Chemical Physics, 148 (124308).
ISSN 0021-9606
Abstract
A detailed characterisation of the luminescence recorded for the 6p 1P1–6s 1S0 transition of atomic barium isolated in annealed solid xenon has been undertaken using two-dimensional excitation–emission
(2D-EE) spectroscopy. In the excitation spectra extracted from the 2D-EE scans, two dominant thermally stable sites were identified, consisting of a classic, three-fold split Jahn-Teller band, labeled the
blue site, and an unusual asymmetric 2 + 1 split band, the violet site. A much weaker band has also
been identified, whose emission is strongly overlapped by the violet site. The temperature dependence
of the luminescence for these sites was monitored revealing that the blue site has a non-radiative channel competing effectively with the fluorescence even at 9.8 K. By contrast, the fluorescence decay
time of the violet site was recorded to be 4.3 ns and independent of temperature up to 24 K. The
nature of the dominant thermally stable trapping sites was investigated theoretically with Diatomicsin-Molecule (DIM) molecular dynamics simulations. The DIM model was parameterized with ab
initio multi-reference configuration interaction calculations for the lowest energy excited states of the
Ba·Xe pair. The simulated absorption spectra are compared with the experimental results obtained
from site-resolved excitation spectroscopy. The simulations allow us to assign the experimental blue
feature spectrum to a tetra-vacancy trapping site in the bulk xenon fcc crystal—a site often observed
when trapping other metal atoms in rare gas matrices. By contrast, the violet site is assigned to
a specific 5-atom vacancy trapping site located at a grain boundary
Item Type: |
Article
|
Additional Information: |
Cite as: Davis BM, Gervais B, McCaffrey JG. An investigation of the sites occupied by atomic barium in solid xenon-A 2D-EE luminescence spectroscopy and molecular dynamics study. J Chem Phys. 2018;148(12):124308. doi:10.1063/1.5019890 |
Keywords: |
investigation; sites occupied;
atomic barium; solid xenon; 2D-EE;
luminescence; spectroscopy; molecular
dynamics; study; |
Academic Unit: |
Faculty of Science and Engineering > Chemistry |
Item ID: |
13102 |
Identification Number: |
https://doi.org/10.1063/1.5019890 |
Depositing User: |
Dr. John McCaffrey
|
Date Deposited: |
24 Jun 2020 16:46 |
Journal or Publication Title: |
Journal of Chemical Physics |
Publisher: |
American Institute of Physics |
Refereed: |
Yes |
URI: |
|
Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
here |
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