Davis, Barry and McCaffrey, John G.
(2018)
Luminescence of Atomic Barium in Rare Gas Matrices: A Two Dimensional Excitation/Emission Spectroscopy Study.
Journal of Physical Chemistry A, 122.
pp. 7339-7350.
ISSN 1089-5639
Abstract
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 1
P1
→ (6s)2 1S0 fluorescence. Extensive use has been made of twodimensional 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 1
P1 ← (6s)2 1S0 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.
Item Type: |
Article
|
Keywords: |
Luminescence; Atomic Barium; Gas Matrices; Two Dimensional; Excitation; Emission; Spectroscopy; Study; |
Academic Unit: |
Faculty of Science and Engineering > Chemistry |
Item ID: |
13107 |
Identification Number: |
https://doi.org/10.1021/acs.jpca.8b05140 |
Depositing User: |
Dr. John McCaffrey
|
Date Deposited: |
26 Jun 2020 21:40 |
Journal or Publication Title: |
Journal of Physical Chemistry A |
Publisher: |
American Chemical Society |
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 |
Repository Staff Only(login required)
|
Item control page |
Downloads per month over past year
Origin of downloads