Brilly, James (1990) XUV photoabsorption studies along extended isoelectronic sequences using a dual laser produced plasma techniques. PhD thesis, Dublin City University.
Abstract
Hot dense plasmas produced when the output of powerful
pulsed laser systems are focused onto targets located in
vacuum have been the subject of extensive study for a
number of years. Such plasmas have found applications
both as intense sources of continuum radiation in the XUV
and as a versatile source of ionic species. In the work
reported here the above properties of the laser produced
plasma were exploited and enabled many new
photoabsorption spectra of ionic species to be recorded
in the XUV region.
Using a dual laser produced plasma technique the XUV
radiation emitted from laser plasmas created on the
surface of a high Z material was used to backlight a
second laser plasma and carry out ionic photoabsorption
studies at wavelengths below 300A. An extensive
examination of a number of isoelectronic sequences was
undertaken. XUV photoabsorption studies were carried out
on members of the neon, sodium, argon, krypton, bromine,
selenium and xenon sequences.
Absorption along the neon like sequence was extended to
the fifth member, Si V. We report here the first
unambiguous photoabsorption spectrum of the neon like
A1 ion showing the principal outer shell transitions
together with 2s inner shell autoionizing features.
Detailed XUV photoabsorption spectra of the Si4+ ion are
reported here for the first time, excitations involving
an inner 2s electron were classified and m the case of
the 2s-»3p transition found to be an example of forced
autoionization. An intensity anomaly in the Beutler Fano
line shape of the 2s->3p member of the autoionizing series
4 in Si was studied with varying plasma conditions.
Absorption studies along the sodium isoelectronic
sequence have resulted in the classification of new lines arising from transitions to core excited autoionizing
2 3 levels in the A1 and Si ions, transitions from ground
and excited states were observed.
XUV photoabsorption spectra of plasmas formed on targets
of elements following argon (scandium and titanium) in
the periodic table were found to be of a complex nature
and to contain contributions from a number of different
ion stages.
Elements following krypton were also studied. Absorption
spectra of laser produced plasmas formed on targets of
strontium, yttrium and zirconium were recorded. The
strontium and yttrium work resulted m 3d->4p transitions
being observed m a number of ion stages for the first
time.
Work along the xenon sequence was found to be in
2
agreement with previous Ba observations Absorption
studies along the sequence were extended to the fifth
member Ce4+. An extensive analysis of the 4d
photoabsorption spectrum of La was carried out and
revealed that the 4d-»4f transition, expected to be the
strongest was not observed. The interpretation of the
spectrum showed that the feature possessed a large
autoionization width and was not present m the
experimental spectrum. The analysis further confirmed
2 that the 4f wave function m Ba is only partially
collapsed.
The work reported here has clearly shown the dual laser
produced plasma technique to be a powerful and versatile
method for recording XUV photoabsorption spectra of
ionized species.
Metadata
Item Type: | Thesis (PhD) |
---|---|
Date of Award: | 1990 |
Refereed: | No |
Supervisor(s): | Kennedy, Eugene T. |
Uncontrolled Keywords: | Continuum radiation; Hot dense plasmas; Ionic species |
Subjects: | Physical Sciences > Laser plasmas |
DCU Faculties and Centres: | DCU Faculties and Schools > Faculty of Science and Health > School of Physical Sciences |
Use License: | This item is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 License. View License |
ID Code: | 19162 |
Deposited On: | 23 Aug 2013 11:08 by Celine Campbell . Last Modified 23 Aug 2013 11:08 |
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