Collisional quenching of OH (A(2)Sigma(+), upsilon'=0) by N-2, O-2 and CO2 between 204 and 294 K. Implications for atmospheric measurements of OH by laser-induced fluorescence

被引:36
作者
Bailey, AE
Heard, DE
Paul, PH
Pilling, MJ
机构
[1] UNIV LEEDS,SCH CHEM,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND
[2] SANDIA NATL LABS,COMBUST RES FACIL,DIV 8351,LIVERMORE,CA 94550
来源
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS | 1997年 / 93卷 / 16期
关键词
D O I
10.1039/a701582h
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
The temperature dependence of the collisional quenching of OH (A 2,,i = O) has been studied in a discharge-flow system between 204 and 294 K for the collision gases N-2, O-2 and CO2. Quenching cross-sections were observed to increase with decreasing temperature, consistent with attractive forces dominating the collision process. For N-2, the cross-section increases from 4.3 +/- 0.1 Angstrom(2) at 294 +/- 1 K to 6.8 +/- 0.2 Angstrom(2) at 204 +/- 1 K, for O-2 from 18.6 +/- 0.6 Angstrom(2) (294 K) to 23.5 + 0.7 Angstrom(2) (204 K) and for CO2 from 62.8 +/- 1.9 Angstrom(2) (292 K) to 75.6 +/- 2.3 Angstrom(2) (204 K). The results are in good agreement with previous determinations, but extend the range to lower temperatures, and are consistent with data obtained at much higher temperatures. The results are also consistent with the cross-section for quenching by air determined at ultra-low temperatures (ca. 25 K) within a supersonic free-jet expansion. A collision complex model incorporating the rotational dependence of quenching using an exponential energy gap law was able to reproduce the data for O-2 and CO2 over the temperature range studied. The experimental results were used to calculate the effective cross-section for quenching of OH (A (2) Sigma(+), OH(A(2) Sigma(+), upsilon' = 0) by air in the range 200-300 K, covering conditions found both in the stratosphere and within the free-jet expansion of instruments used to measure tropospheric OH by low-pressure laser-induced fluorescence. The fluorescence quantum yield was calculated to change by ca. 25% in this range because of changes in quenching rate, directly affecting instrument calibrations and hence their sensitivity for OH detection.
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页码:2915 / 2920
页数:6
相关论文
共 27 条
[1]  
BOHMER E, 1992, J CHEM PHYS, V97, P2536, DOI 10.1063/1.463092
[2]   TEMPERATURE-DEPENDENT ELECTRONIC QUENCHING OF OH(A-2-SIGMA+, V' = 0) [J].
COPELAND, RA ;
CROSLEY, DR .
JOURNAL OF CHEMICAL PHYSICS, 1986, 84 (06) :3099-3105
[3]   ROTATIONAL-LEVEL-DEPENDENT QUENCHING OF A 2-SIGMAT OH AND OD [J].
COPELAND, RA ;
DYER, MJ ;
CROSLEY, DR .
JOURNAL OF CHEMICAL PHYSICS, 1985, 82 (09) :4022-4032
[4]   ROTATIONAL LEVEL DEPENDENCE OF ELECTRONIC QUENCHING OF OH(A-2-SIGMA+,NU'=O) [J].
COPELAND, RA ;
CROSLEY, DR .
CHEMICAL PHYSICS LETTERS, 1984, 107 (03) :295-300
[5]   Implementation and initial deployment of a field instrument for measurement of OH and HO2 in the troposphere by laser-induced fluorescence [J].
Creasey, DJ ;
HalfordMaw, PA ;
Heard, DE ;
Pilling, MJ ;
Whitaker, BJ .
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, 1997, 93 (16) :2907-2913
[6]  
CREASEY DJ, 1997, IN PRESS APPL PHYS B
[7]  
CROSLEY DR, 1995, CURRENT PROBLEMS PRO, P256
[8]  
CROSLEY DR, 1992, NASA C PUBL, V3245, P1
[9]   COLLISIONAL QUENCHING OF A2-SIGMA+ OH AT ELEVATED-TEMPERATURES [J].
FAIRCHILD, PW ;
SMITH, GP ;
CROSLEY, DR .
JOURNAL OF CHEMICAL PHYSICS, 1983, 79 (04) :1795-1807
[10]   DIRECT MEASUREMENT OF RADIATIVE LIFETIMES OF A SIGMA-2+ (V' = O) STATES OF OH AND OD [J].
GERMAN, KR .
JOURNAL OF CHEMICAL PHYSICS, 1975, 62 (07) :2584-2587