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Title: Trace species detection: Spectroscopy and molecular energy transfer at high temperature

Abstract

Monitoring the concentration of trace species such as atomic and molecular free radicals is essential in forming predictive models of combustion processes. LIF-based techniques have the necessary sensitivity for concentration and temperature measurements but have limited accuracy due to collisional quenching in combustion applications. The goal of this program is to use spectroscopic and kinetic measurements to quantify nonradiative and collisional effects on LIF signals and to develop new background-free alternatives to LIF. The authors have measured the natural linewidth of several OH A-X (3,0) rotational transitions to determine predissociation lifetimes in the upper state, which were presumed to be short compared to quenching lifetimes, and as a result, quantitative predictions about the applicability of predissociation fluorescence methods at high pressures are made. The authors are investigating collisional energy transfer in the A-state of NO. Quenching rates which enable direct corrections to NO LIF quantum yields at high temperature were calculations. These quenching rates are now being used in studies of turbulence/chemistry interactions. The authors have measured the electric dipole moment {mu} of excited-state NO using Stark quantum-beat spectroscopy. {mu} is an essential input to a harpoon model which predicts quenching efficiencies for NO (A) by a variety of combustion-relatedmore » species. The authors are developing new coherent multiphoton techniques for measurements of atomic hydrogen concentration in laboratory flames to avoid the quenching problems associated with previous multiphoton LIF schemes.« less

Authors:
 [1]
  1. Sandia National Laboratories, Livermore, CA (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
OSTI Identifier:
139879
Report Number(s):
BNL-48923; CONF-9306172-
ON: DE93015758; TRN: 93:002191-0033
Resource Type:
Conference
Resource Relation:
Conference: 15. combustion research contractors` meeting, Lake Harmony, PA (United States), 2-4 Jun 1993; Other Information: PBD: 1993; Related Information: Is Part Of Fifteenth combustion research conference; PB: 391 p.
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 02 PETROLEUM; NITRIC OXIDE; FLUORESCENCE SPECTROSCOPY; HYDROXYL RADICALS; ENERGY TRANSFER; COMBUSTION; QUENCHING; PREDISSOCIATION; FLUORESCENCE; TURBULENCE; FLAMES; ROTATIONAL STATES

Citation Formats

Gray, J A. Trace species detection: Spectroscopy and molecular energy transfer at high temperature. United States: N. p., 1993. Web.
Gray, J A. Trace species detection: Spectroscopy and molecular energy transfer at high temperature. United States.
Gray, J A. 1993. "Trace species detection: Spectroscopy and molecular energy transfer at high temperature". United States. https://www.osti.gov/servlets/purl/139879.
@article{osti_139879,
title = {Trace species detection: Spectroscopy and molecular energy transfer at high temperature},
author = {Gray, J A},
abstractNote = {Monitoring the concentration of trace species such as atomic and molecular free radicals is essential in forming predictive models of combustion processes. LIF-based techniques have the necessary sensitivity for concentration and temperature measurements but have limited accuracy due to collisional quenching in combustion applications. The goal of this program is to use spectroscopic and kinetic measurements to quantify nonradiative and collisional effects on LIF signals and to develop new background-free alternatives to LIF. The authors have measured the natural linewidth of several OH A-X (3,0) rotational transitions to determine predissociation lifetimes in the upper state, which were presumed to be short compared to quenching lifetimes, and as a result, quantitative predictions about the applicability of predissociation fluorescence methods at high pressures are made. The authors are investigating collisional energy transfer in the A-state of NO. Quenching rates which enable direct corrections to NO LIF quantum yields at high temperature were calculations. These quenching rates are now being used in studies of turbulence/chemistry interactions. The authors have measured the electric dipole moment {mu} of excited-state NO using Stark quantum-beat spectroscopy. {mu} is an essential input to a harpoon model which predicts quenching efficiencies for NO (A) by a variety of combustion-related species. The authors are developing new coherent multiphoton techniques for measurements of atomic hydrogen concentration in laboratory flames to avoid the quenching problems associated with previous multiphoton LIF schemes.},
doi = {},
url = {https://www.osti.gov/biblio/139879}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Dec 01 00:00:00 EST 1993},
month = {Wed Dec 01 00:00:00 EST 1993}
}

Conference:
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