A Laser Produced Plasma as a Pulsed Source of Continuum Infrared Radiation for Time Resolved Absorption Spectroscopy.
UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF CHEMISTRY
Pagination or Media Count:
The focussed beam from the 20 ns pulse of an amplified Nd glass laser produces a high temperature plasma in air or other media. Such plasmas, while well known as phenomena, seem not to have been investigated as a source of infrared radiation. We find the emission in the chemical infrared region, 2100-1700CM, to be a continuum or white, and at least twenty five times more intense than that from a typical glow bar used in conventional infrared absorption spectroscopy. Emission from the plasma formed in air decays with a wavelength dependent lifetime, about 150 ns for the visible portion, and 2 microsecond for the infrared portion. When formed in argon, the plasma emission is more intense, and the decay time of the infrared emission rises to 4 microsec. Use of this source is demonstrated in a measurement of the carbonyl stretching absorption for WC06 and plans are to apply the method to the determination of infrared absorption spectra of thermally equilibrated excited states of organic molecules and of coordination compounds.
- Lasers and Masers
- Infrared Detection and Detectors
- Atomic and Molecular Physics and Spectroscopy