History of Atomic Spectroscopy at NIST
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The Atomic Spectroscopy Group at the National Institute of Standards and
Technology (NIST) has a long history of contributions to optical science and
metrology. The Group was headed for many years by William F. Meggers,
who early in his career used interferometric methods to measure the index of
refraction of air over a wide wavelength region. Later he spearheaded the
development of infrared sensitive emulsions, which he used for aerial
photography and to photograph the sun in the infrared. His great interest in
spectroscopy led him to investigate the spectra of nearly every element, and
in the process lay the foundation for modern analytical spectroscopy. In
order to organize and disseminate the vast amount of information on atomic
spectra and energy levels that had accumulated through the years, Meggers
brought Charlotte Moore Sitterly to NIST. Charlotte Sitterly published the
classic volumes on Atomic Energy Levels and established what today has
become the NIST Data Centers on Atomic Spectroscopy. These Data Centers, one on
Atomic Energy Levels and one on Atomic Transition Probabilities and Line
Shapes, carry out critical compilations and maintain large databases of atomic
spectroscopic data, most of which are available on the World Wide Web.
When Meggers retired from NIST in 1958, he was succeeded as leader of the group
by Karl G. Kessler. After a few years Kessler went on to higher management
at NIST. In 1961 William C. Martin began a leadership of the Group that
lasted nearly forty years. In the early years of his leadership the Group
greatly expanded in number of staff members, and its interests were broadened
to include precision measurements by laser spectroscopy and applications to
astrophysics and diagnostics of plasmas found in fusion research devices and
commercial lighting devices. Although astronomers had always been prime users
of spectroscopic data, the advent of space-based observatories intensified this
application, especially though the pressing need for extensive spectroscopic
data in the vacuum ultraviolet. Martin retired in 1998 and was succeeded as
Group Leader by Joseph Reader. Although officially retired, Martin continues
actively as Scientist Emeritus.
Current laboratory projects of the Group include data for space astrophysics,
high precision measurements by Fourier transform and laser spectroscopy, high
accuracy measurements of light sources used for wavelength calibration of
microlithography lasers, data on highly-ionized atoms for diagnostics of fusion
energy devices, development of methods for diagnostics of high-intensity
lighting sources by x-ray absorption and fluorescence, and tests of the use of
image plates for vacuum ultraviolet spectroscopy. Data Center projects include
compilations of wavelengths and energy levels for the rare gases, tungsten,
rubidium, cesium, barium, beryllium, and gallium in all stages of ionization.
Transition probabilities are being compiled for Fe I
and Fe II, Na in all stages of ionization, and
other light elements of astrophysical importance, such as S, Si, Mg, and Ne.
Our web-based databases such as the Atomic Spectra Database and the
Bibliographic Database on Atomic Transition Probabilities continue to be
expanded and improved. Theoretical work is carried out on electron impact
cross sections for excitation and ionization of atoms and molecules for fusion
science applications. These results are also available on the World Wide
Web.
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Online: July 2002 - Last update: April 2004
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