Accession Number:

ADA318479

Title:

New High-Pressure Diagnostic Technique.

Descriptive Note:

Final technical rept. 1 Aug 93-31 Jul 96,

Corporate Author:

STANFORD UNIV CA DEPT OF CHEMISTRY

Personal Author(s):

Report Date:

1996-10-21

Pagination or Media Count:

8.0

Abstract:

Our research goal was to develop nonintrusive, laser-based optical diagnostic tools for the investigation of trace amounts of molecular species in hostile environments such as plasmas, flashes, flames and other combustion forms. By extending our study on spectroscopic applications of degenerate four-wave mixing DFWM, we proposed to exploit a new absorption technique, Cavity Ring-Down Spectroscopy CRDS, which is, in many ways, complementary to other methods for the investigation of the transient species, radicals, and ions present in harsh luminous environments. A spatial profile of CH3 absolute concentration near the hot filament was determined by CRDS using a topological method - Abel inversion of the spatial profile of CH3 absorbance. No rotational lines are resolved from CH3 because of predissociation. A two-photon laser-induced fluorescence LIF scheme is proposed to measure atomic hydrogen. The spatial temperature profile near the filament at 20 Torr of pure H2 at different filament temperatures was measured in the same reactor we measured CH3. This measurement, combined with the CH3 spatial profile gives a better understanding of the two most important gas phase radical species in the hot-filament diamond CVD process.

Subject Categories:

  • Lasers and Masers
  • Inorganic Chemistry
  • Physical Chemistry
  • Atomic and Molecular Physics and Spectroscopy
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE