Rate coefficient for the gas phase reaction of NaOH with CO<sub>2</sub>

Ager, Joel W.; Howard, Carleton J.

doi:10.1029/jd092id06p06675

Cited by 28 publications

(16 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…atomic H, which is rather slow [Ager and Howard, 1987], and so NaHCO 3 should be stable at 95 km. Thus, NaHCO 3 probably fulfils the first two criteria for a reservoir.…”

Section: Rajasekhar and Plane [1993] Have Shown From Ab Initio Quantumentioning

confidence: 99%

A modelling investigation of sudden sodium layers

Cox¹,

Plane²,

Green³

1993

Geophysical Research Letters

View full text Add to dashboard Cite

A time‐resolved model, incorporating both vertical diffusion and chemistry, indicates that the minimum source strength required to produce a typical sudden sodium layer (SSL) is about 3 Na atoms cm−3s−1. However, many of the mechanisms proposed to explain the formation of SSLs are not able realistically to provide this source strength, or the source strength of about 1 Na atom cm−3s−1 that is required to maintain an SSL over several hours. Furthermore, the sodium reservoirs do not appear to contain sufficient sodium to produce an SSL, although sodium ions (Na+), and meteoric dust coated with sodium compounds, cannot be ruled out. An additional mechanism is proposed, namely, the release of atomic Na by dissociative electron attachment to sodium‐containing silicate molecules (e.g. Na2SiO3 or NaAlSiO4) that are produced by meteoric ablation.

show abstract

“…atomic H, which is rather slow [Ager and Howard, 1987], and so NaHCO 3 should be stable at 95 km. Thus, NaHCO 3 probably fulfils the first two criteria for a reservoir.…”

Section: Rajasekhar and Plane [1993] Have Shown From Ab Initio Quantumentioning

confidence: 99%

A modelling investigation of sudden sodium layers

Cox¹,

Plane²,

Green³

1993

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…Unlike the first two of these postulated sinks, for which there is in fact little evidence, the reactions shown in Figure 1 which produce NaHCO3 from atomic Na have all been studied in the laboratory at appropriately low temperatures [Plane and Helmer, 1994]. Furthermore, reaction (R17), which converts the bicarbonate back to Na by reaction with atomic H (see Table 1), has been shown to be very slow [Ager and Howard, 1987b]. Thus, NaHCO3 is probably the dominant sink for sodium below the layer.…”

Section: Introductionmentioning

confidence: 99%

Mesospheric Na layer at extreme high latitudes in summer

Plane¹,

Cox²,

Qian³

et al. 1998

J. Geophys. Res.

View full text Add to dashboard Cite

Abstract. Summertime observations of the mesospheric Na layer at high latitudes are reported from the 1993 Airbome Noctilucent Cloud (ANLC-93) campaign in the Canadian Arctic and at the Amundsen-Scott South Pole Station. Measurements at the South Pole reveal a layer that has a smaller column abundance and is significantly higher and thinner than at midlatitudes. Using a model that was essentially optimized to wintertime conditions at high northern latitudes, the South Pole layer can be modeled satisfactorily if the rate coefficient for the reaction between sodium bicarbonate and atomic hydrogen is set to k(NaHCO3 + H • Na + H20 + CO2) = 1.1 x 10 -• exp (-910/T) cm 3 molecule 4 s 4. In particular, the model is able to reproduce the small scale height of about 2 km observed on the underside of the layer. It is then shown that this steep gradient in the atomic Na mixing ratio can be sustained against vertical eddy diffusion because of the sufficiently rapid chemical cycling between Na its major reservoir, NaHCO3. This justifies the assumption in the model that the vertical transport of Na species can be treated in terms of a single continuity equation describing total sodium. The observations from the campaigns in both hemispheres show that the Na abundance has a temperature dependence of about 2 x 108 cm -2 K 4 at temperatures below 170 K, in good accord with the model. About 40% of this dependence appears to be caused by the activation energies of the reactions that partition sodium between atomic Na and NaHCO3, and the remainder by the temperature dependence of the odd-oxygen/odd-hydrogen chemistry in the upper mesosphere.

show abstract

“…11b. Assuming that the reaction was in the low pressure limit, 17 a linear fit to the data would yield the following low pressure limit rate constant: be k 4,0 (305 K, P < 4 Torr) = (7.6 ± 1.6) x 10 -29 cm 6 molecule -2 s -1 (2 ).…”

Section: Reaction Of Naoh With Comentioning

confidence: 99%

“…12,16 R3 was investigated previously only by Ager and Howard, 11 who observed both channels, although the branching ratio = k 3b /k 3 was not quantified. The pressure-dependent rate constants of R4 and R5 were measured by Ager and Howard 17,18 who titrated NaOH and NaO with H and NO, respectively, to make Na. The rate constant of R6 has not been reported previously.…”

mentioning

confidence: 99%

Reaction Kinetics of Meteoric Sodium Reservoirs in the Upper Atmosphere

2015

View full text Add to dashboard Cite

The gas-phase reactions of a selection of sodium-containing species with atmospheric constituents, relevant to the chemistry of meteor-ablated Na in the upper atmosphere, were studied in a fast flow tube using multi-photon ionisation time-of-flight mass spectrometry.For the first time unambiguous observations of NaO and NaOH in the gas phase under atmospheric conditions have been achieved. This enabled the direct measurement of the rate constants for the reactions of NaO with H 2 , H 2 O and CO, and of NaOH with CO 2 , which at 300-310 K were found to be (at 2 confidence level): k(NaO + H 2 O) = (2.4 ± 0.6)  10 -10 cm 3 molecule -1 s -1 , k(NaO + H 2 ) = (4.9 ± 1.2)  10 -12 cm 3 molecule -1 s -1 , k(NaO + CO) = (9 ± 4)  10 -11 cm 3 molecule -1 s -1 , and k(NaOH + CO 2 + M) = (7.6 ± 1.6)  10 -29 cm 6 molecule -2 s -1 (P = 1 -4 Torr). The NaO + H 2 reaction was found to make NaOH with a branching ratio ≥ 99%. A combination of quantum chemistry and statistical rate theory calculations are used to interpret the reaction kinetics and extrapolate the atmospherically relevant experimental results to mesospheric temperatures and pressures. The NaO + H 2 O and NaOH + CO 2 reactions act sequentially to provide the major atmospheric sink of meteoric Na, and therefore have a significant impact on the underside of the Na layer in the terrestrial mesosphere: the newly determined rate constants shift the modelled peak to about 93 km, i.e. two km higher than observed by ground-based lidars. This highlights further uncertainties in the Na chemistry cycle such as the unknown rate constant of the NaOH + H reaction. The fast Narecycling reaction between NaO and CO and a re-evaluated rate constant of the NaO + CO 2 sink should be now considered in chemical models of the Martian Na layer.

show abstract

Rate coefficient for the gas phase reaction of NaOH with CO₂

Cited by 28 publications

References 18 publications

A modelling investigation of sudden sodium layers

A modelling investigation of sudden sodium layers

Mesospheric Na layer at extreme high latitudes in summer

Reaction Kinetics of Meteoric Sodium Reservoirs in the Upper Atmosphere

Contact Info

Product

Resources

About

Rate coefficient for the gas phase reaction of NaOH with CO2

Cited by 28 publications

References 18 publications

A modelling investigation of sudden sodium layers

A modelling investigation of sudden sodium layers

Mesospheric Na layer at extreme high latitudes in summer

Reaction Kinetics of Meteoric Sodium Reservoirs in the Upper Atmosphere

Contact Info

Product

Resources

About

Rate coefficient for the gas phase reaction of NaOH with CO₂