LASER-INDUCED FLAME CHEMISTRY OF LI (22P1/2,3/2) AND NA (32P1/2,3/2) - IMPLICATIONS FOR OTHER SATURATED MODE MEASUREMENTS

被引:40
作者
MULLER, CH [1 ]
SCHOFIELD, K [1 ]
STEINBERG, M [1 ]
机构
[1] UNIV CALIF SANTA BARBARA, INST QUANTUM, SANTA BARBARA, CA 93106 USA
关键词
D O I
10.1063/1.439120
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Saturated laser fluorescence measurements of sodium or lithium in a series of fuel rich, atmospheric pressure H2/O2/N2 flames at 1700-2200 K indicate induced chemical interactions between the excited 2P1/2,3/2 states of the metals and the H2O or H2 flame constituents. A steady state redistribution occurs among the metal's elemental, hydroxide and hydride forms within the initial fraction of the μs laser pulse duration. A saturated absorption model incorporating these chemical effects illustrates the significant depletion of the free atom concentrations under these conditions and explains previous discrepancies between such measurements and conventional absorption experiments. Estimates of the rates of the reactions between the 2P1/2,3/2 in states of sodium or lithium with H2O or H2 indicate that they proceed predominantly via the nonadiabatic physical relaxation channel. For sodium the two chemical channels are relatively inefficient constituting only about 2% and 0.5% of the total interaction cross section with H2O and H2, respectively. Even so, they are still sufficient to drain off a reasonable fraction of the free atoms into these molecular metastable sinks. No evidence of contributions from laser enhanced ionization was noted. Applications of the saturated laser fluorescence technique as a general combustion species monitor must necessarily be restricted to the use of nanosecond pulse length lasers in order to circumvent these potential chemical relaxations. © 1980 American Institute of Physics.
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页码:6620 / 6631
页数:12
相关论文
共 77 条
[1]  
ALLEN JE, 1979, S INT COMBUST P, V17, P797
[2]  
Anderson W. R., 1979, 10th Materials Research Symposium on Characterisation of High Temperature Vapors and Gases, P1153
[3]   KINETICS OF COLLISIONAL IONIZATION OF ALKALI-METAL ATOMS AND RECOMBINATION OF ELECTRONS WITH ALKALI-METAL IONS IN FLAMES [J].
ASHTON, AF ;
HAYHURST, AN .
COMBUSTION AND FLAME, 1973, 21 (01) :69-75
[4]   MODIFIED-MODEL FOR QUENCHING AND ELECTRONIC-VIBRATIONAL ENERGY-TRANSFER [J].
BARKER, JR .
CHEMICAL PHYSICS, 1976, 18 (1-2) :175-188
[5]   MEASUREMENT OF C2 CONCENTRATIONS IN AN OXYGEN-ACETYLENE FLAME - APPLICATION OF SATURATION SPECTROSCOPY [J].
BARONAVSKI, AP ;
MCDONALD, JR .
JOURNAL OF CHEMICAL PHYSICS, 1977, 66 (07) :3300-3301
[6]   APPLICATION OF SATURATION SPECTROSCOPY TO MEASUREMENT OF C2, 3IIU CONCENTRATIONS IN OXY-ACETYLENE FLAMES [J].
BARONAVSKI, AP ;
MCDONALD, JR .
APPLIED OPTICS, 1977, 16 (07) :1897-1901
[7]   QUENCHING OF RUBIDIUM RESONANCE RADIATION BY NITROGEN AND NOBLE GASES [J].
BELLISIO, JA ;
DAVIDOVI.P ;
KINDLMAN.PJ .
JOURNAL OF CHEMICAL PHYSICS, 1968, 48 (05) :2376-&
[8]   ROTATIONAL REDISTRIBUTION EFFECT ON SATURATED LASER-INDUCED FLUORESCENCE [J].
BERG, JO ;
SHACKLEFORD, WL .
APPLIED OPTICS, 1979, 18 (13) :2093-2094
[9]   SATURATION IN LASER-EXCITED ATOMIC FLUORESCENCE SPECTROMETRY - EXPERIMENTAL-VERIFICATION [J].
BLACKBURN, MB ;
MERMET, JM ;
BOUTILIER, GD ;
WINEFORDNER, JD .
APPLIED OPTICS, 1979, 18 (11) :1804-1807
[10]   MEASUREMENT OF CH AND CN CONCENTRATION IN FLAMES BY LASER-INDUCED SATURATED FLUORESCENCE [J].
BONCZYK, PA ;
SHIRLEY, JA .
COMBUSTION AND FLAME, 1979, 34 (03) :253-264