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Time Resolved Laser Spectroscopy of Rydberg States in Group IIIA and IIIA Elements

Jönsson, Göran LU (1984) In Lund Reports in Atomic Physics LRAP-38.
Abstract
In this work radiative properties of neutral elements with one or

two electrons outside closed subshells have been investigated.

Using laser techniques in connection with atomic beams selective

excitation of Rydberg states was performed. Most of the studied

states were populated with two-step excitation. Some states were

reached directly from the ground state or from a metastable state

and occasionally two-photon absorption was used. The excitation

sometimes involved the use of frequency-doubling and Raman-

shifting techniques.

By time-resolved detection of the decay light from an excited

state, primarily information on the radiative lifetime is... (More)
In this work radiative properties of neutral elements with one or

two electrons outside closed subshells have been investigated.

Using laser techniques in connection with atomic beams selective

excitation of Rydberg states was performed. Most of the studied

states were populated with two-step excitation. Some states were

reached directly from the ground state or from a metastable state

and occasionally two-photon absorption was used. The excitation

sometimes involved the use of frequency-doubling and Raman-

shifting techniques.

By time-resolved detection of the decay light from an excited

state, primarily information on the radiative lifetime is obtained.

With two different experimental arrangements radiative

lifetimes in several Rydberg states have been determined. Using

the quantum-beat technique time-resolved detection also provides

information on energy splittings. This technique was used

to measure hyperfine-structure splittings.To obtain information

about hyperfine-structure constants and isotope shifts high-

resolution spectroscopy on a collimated atomic beam was also

employed.

The behaviour of highly excited alkali atoms is mostly hydrogen-

like and well predicted by theory. Group III A elements have one

electron outside a closed subshell and are expected to behave

like alkali atoms. The situation is however complicated by the

presence of doubly excited states. Configuration interaction can

then cause a partial mixing between singly and doubly excited

states. In the alkaline-earth atoms (group II A elements), having

two electrons outside closed shells, the situation is similar. In

a Rydberg series of one excited electron the admixture of doubly

excited states can cause large deviations from hydrogenic behaviour.

Another complication in the alkaline-earth atoms is the

mixture of singlet- and triplet states.

- 4 -

The presented results from measurements made on Na, Mg, Ca, Sr,

Ba, Al, Ga and In will primarily serve as a basis for tests of

modern atomic-physics models. Some of the lifetime values are

also of astrophysical interest.

Keywords: Laser spectroscopy, Rydberg states, time resolved, high

resolution, two-step excitation, metastable state, two-photon

absorption, frequency doubling, Raman shifting, radiative lifetime,

quantum beat, hyperfine structure, isotope shift, Stark

shift, alkali atoms, group III A elements, alkaline-earth atoms,

configuration interaction, singlet-triplet mixing. (Less)
Please use this url to cite or link to this publication:
author
supervisor
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  • unknown], [unknown
organization
publishing date
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Thesis
publication status
published
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in
Lund Reports in Atomic Physics
volume
LRAP-38
pages
119 pages
publisher
Division of Atomic Physics, Department of Physics, Faculty of Engineering, LTH, Lund University
defense location
n/a
defense date
1984-01-01 01:01
language
English
LU publication?
yes
id
1fad2fdf-6bc0-4436-bcd6-2b7478ab122a (old id 2260427)
date added to LUP
2012-01-25 15:13:48
date last changed
2016-09-19 08:45:07
@misc{1fad2fdf-6bc0-4436-bcd6-2b7478ab122a,
  abstract     = {In this work radiative properties of neutral elements with one or<br/><br>
two electrons outside closed subshells have been investigated.<br/><br>
Using laser techniques in connection with atomic beams selective<br/><br>
excitation of Rydberg states was performed. Most of the studied<br/><br>
states were populated with two-step excitation. Some states were<br/><br>
reached directly from the ground state or from a metastable state<br/><br>
and occasionally two-photon absorption was used. The excitation<br/><br>
sometimes involved the use of frequency-doubling and Raman-<br/><br>
shifting techniques.<br/><br>
By time-resolved detection of the decay light from an excited<br/><br>
state, primarily information on the radiative lifetime is obtained.<br/><br>
With two different experimental arrangements radiative<br/><br>
lifetimes in several Rydberg states have been determined. Using<br/><br>
the quantum-beat technique time-resolved detection also provides<br/><br>
information on energy splittings. This technique was used<br/><br>
to measure hyperfine-structure splittings.To obtain information<br/><br>
about hyperfine-structure constants and isotope shifts high-<br/><br>
resolution spectroscopy on a collimated atomic beam was also<br/><br>
employed.<br/><br>
The behaviour of highly excited alkali atoms is mostly hydrogen-<br/><br>
like and well predicted by theory. Group III A elements have one<br/><br>
electron outside a closed subshell and are expected to behave<br/><br>
like alkali atoms. The situation is however complicated by the<br/><br>
presence of doubly excited states. Configuration interaction can<br/><br>
then cause a partial mixing between singly and doubly excited<br/><br>
states. In the alkaline-earth atoms (group II A elements), having<br/><br>
two electrons outside closed shells, the situation is similar. In<br/><br>
a Rydberg series of one excited electron the admixture of doubly<br/><br>
excited states can cause large deviations from hydrogenic behaviour.<br/><br>
Another complication in the alkaline-earth atoms is the<br/><br>
mixture of singlet- and triplet states.<br/><br>
- 4 -<br/><br>
The presented results from measurements made on Na, Mg, Ca, Sr,<br/><br>
Ba, Al, Ga and In will primarily serve as a basis for tests of<br/><br>
modern atomic-physics models. Some of the lifetime values are<br/><br>
also of astrophysical interest.<br/><br>
Keywords: Laser spectroscopy, Rydberg states, time resolved, high<br/><br>
resolution, two-step excitation, metastable state, two-photon<br/><br>
absorption, frequency doubling, Raman shifting, radiative lifetime,<br/><br>
quantum beat, hyperfine structure, isotope shift, Stark<br/><br>
shift, alkali atoms, group III A elements, alkaline-earth atoms,<br/><br>
configuration interaction, singlet-triplet mixing.},
  author       = {Jönsson, Göran},
  language     = {eng},
  pages        = {119},
  publisher    = {ARRAY(0x8a69880)},
  series       = {Lund Reports in Atomic Physics},
  title        = {Time Resolved Laser Spectroscopy of Rydberg States in Group IIIA and IIIA Elements},
  volume       = {LRAP-38},
  year         = {1984},
}