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Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. March 2006, Volume 5, Number 3, 150-167 |
The C3 Puzzle: Formation of and Spontaneous Emission from the
C3 Radical in Carbon Plasma
László Nemes, Anna M. Keszler, Christian G. Parigger, James O. Hornkohl, Hope A. Michelsen, and Vadim Stakhursky
Internet Electron. J. Mol. Des. 2006, 5, 150-167
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Abstract:
In this review work we address the problem of observing
spontaneous emission from the Swings transitions of the C3
radical in laser-generated graphite plasma. We summarize the
spectroscopy of the C3 radical in carbon vapor and plasma,
sketch the chemical routes leading to this carbon cluster
under plasma conditions, review some theoretical
calculations, and then present our own emission
spectroscopy, experimental investigations. We report time-averaged,
laser-induced optical breakdown spectra from
Nd:YAG laser generated graphite micro-plasma. In 200-300
torr of argon and helium, a weak emission continuum was
observed centered at 400 nm when using laser fluence of
about 1 J cm-2. We conclude that observation of the 400 nm
carbon plasma continuum depends critically on the
experimental configuration. Assignment of this continuum to
the C3 radical is not as straightforward as may have been
thought previously. Further possibilities are considered for
the origin of this continuum.
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