Nitrogen Dioxide Release in the 302 nm Band Photolysis of Spray-Frozen Aqueous Nitrate Solutions. Atmospheric Implications
We quantify the NO_2 fluxes released into the gas phase during the continuous λ ∼ 300 nm photolysis of NO_3^- in submillimeter ice layers produced by freezing aqueous KNO_3 sprays on cold surfaces. Fluxes, F_(NO_2), increase weakly with [NO_3^-] between 5 ≤ [NO_3^-]/mM ≤ 50 and increase marke...
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American Chemical Society
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ftcaltechauth:oai:authors.library.caltech.edu:6a5jn-v5y52 2024-06-23T07:46:41+00:00 Nitrogen Dioxide Release in the 302 nm Band Photolysis of Spray-Frozen Aqueous Nitrate Solutions. Atmospheric Implications Dubowski, Yael Colussi, A. J. Hoffmann, M. R. 2001-05-24 https://doi.org/10.1021/jp0042009 unknown American Chemical Society https://doi.org/10.1021/jp0042009 oai:authors.library.caltech.edu:6a5jn-v5y52 eprintid:58485 resolverid:CaltechAUTHORS:20150623-154758203 info:eu-repo/semantics/closedAccess Other Journal of Physical Chemistry A, 105(20), 4928-4932, (2001-05-24) info:eu-repo/semantics/article 2001 ftcaltechauth https://doi.org/10.1021/jp0042009 2024-06-12T01:53:42Z We quantify the NO_2 fluxes released into the gas phase during the continuous λ ∼ 300 nm photolysis of NO_3^- in submillimeter ice layers produced by freezing aqueous KNO_3 sprays on cold surfaces. Fluxes, F_(NO_2), increase weakly with [NO_3^-] between 5 ≤ [NO_3^-]/mM ≤ 50 and increase markedly with temperature in the range of 268 ≥ T/K ≥ 248. We found that F_(NO_2), the photostationary concentration of NO_2^- (another primary photoproduct), and the quantum yield of 2-nitrobenzaldehyde in situ photoisomerization are nearly independent of ice layer thickness d within 80 ≤ d/μm ≤ 400. We infer that radiation is uniformly absorbed over the depth of the ice layers, where NO_3^- is photodecomposed into NO_2 (+ OH) and NO_2^- (+ O), but that only the NO_2 produced on the uppermost region is able to escape into the gas phase. The remainder is trapped and further photolyzed into NO. We obtain φ_(NO_2^−) ∼ 4.8 × 10^(-3) at 263 K, i.e., about the quantum yield of nitrite formation in neutral NO_3^- aqueous solutions, and an apparent quantum yield of NO2 release φ'_(NO_2) ∼ 1.3 × 10^(-3) that is about a factor of 5 smaller than solution φ_(OH) data extrapolated to 263 K. These results suggest that NO_3^- photolysis in ice takes place in a liquidlike environment and that actual φ'_(NO_2) values may depend on the morphology of ice deposits. Present φ'_(NO_2) data, in conjunction with snow albedo and absorptivity data, lead to F_(NO_2) values in essential agreement with recent measurements in Antarctic snow under solar illumination. © 2001 American Chemical Society. Received: November 14, 2000; In Final Form: March 7, 2001. We are grateful for research funds provided by the foundation Environmental Now. Article in Journal/Newspaper Antarc* Antarctic Caltech Authors (California Institute of Technology) Antarctic The Journal of Physical Chemistry A 105 20 4928 4932 |
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Caltech Authors (California Institute of Technology) |
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description |
We quantify the NO_2 fluxes released into the gas phase during the continuous λ ∼ 300 nm photolysis of NO_3^- in submillimeter ice layers produced by freezing aqueous KNO_3 sprays on cold surfaces. Fluxes, F_(NO_2), increase weakly with [NO_3^-] between 5 ≤ [NO_3^-]/mM ≤ 50 and increase markedly with temperature in the range of 268 ≥ T/K ≥ 248. We found that F_(NO_2), the photostationary concentration of NO_2^- (another primary photoproduct), and the quantum yield of 2-nitrobenzaldehyde in situ photoisomerization are nearly independent of ice layer thickness d within 80 ≤ d/μm ≤ 400. We infer that radiation is uniformly absorbed over the depth of the ice layers, where NO_3^- is photodecomposed into NO_2 (+ OH) and NO_2^- (+ O), but that only the NO_2 produced on the uppermost region is able to escape into the gas phase. The remainder is trapped and further photolyzed into NO. We obtain φ_(NO_2^−) ∼ 4.8 × 10^(-3) at 263 K, i.e., about the quantum yield of nitrite formation in neutral NO_3^- aqueous solutions, and an apparent quantum yield of NO2 release φ'_(NO_2) ∼ 1.3 × 10^(-3) that is about a factor of 5 smaller than solution φ_(OH) data extrapolated to 263 K. These results suggest that NO_3^- photolysis in ice takes place in a liquidlike environment and that actual φ'_(NO_2) values may depend on the morphology of ice deposits. Present φ'_(NO_2) data, in conjunction with snow albedo and absorptivity data, lead to F_(NO_2) values in essential agreement with recent measurements in Antarctic snow under solar illumination. © 2001 American Chemical Society. Received: November 14, 2000; In Final Form: March 7, 2001. We are grateful for research funds provided by the foundation Environmental Now. |
format |
Article in Journal/Newspaper |
author |
Dubowski, Yael Colussi, A. J. Hoffmann, M. R. |
spellingShingle |
Dubowski, Yael Colussi, A. J. Hoffmann, M. R. Nitrogen Dioxide Release in the 302 nm Band Photolysis of Spray-Frozen Aqueous Nitrate Solutions. Atmospheric Implications |
author_facet |
Dubowski, Yael Colussi, A. J. Hoffmann, M. R. |
author_sort |
Dubowski, Yael |
title |
Nitrogen Dioxide Release in the 302 nm Band Photolysis of Spray-Frozen Aqueous Nitrate Solutions. Atmospheric Implications |
title_short |
Nitrogen Dioxide Release in the 302 nm Band Photolysis of Spray-Frozen Aqueous Nitrate Solutions. Atmospheric Implications |
title_full |
Nitrogen Dioxide Release in the 302 nm Band Photolysis of Spray-Frozen Aqueous Nitrate Solutions. Atmospheric Implications |
title_fullStr |
Nitrogen Dioxide Release in the 302 nm Band Photolysis of Spray-Frozen Aqueous Nitrate Solutions. Atmospheric Implications |
title_full_unstemmed |
Nitrogen Dioxide Release in the 302 nm Band Photolysis of Spray-Frozen Aqueous Nitrate Solutions. Atmospheric Implications |
title_sort |
nitrogen dioxide release in the 302 nm band photolysis of spray-frozen aqueous nitrate solutions. atmospheric implications |
publisher |
American Chemical Society |
publishDate |
2001 |
url |
https://doi.org/10.1021/jp0042009 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Journal of Physical Chemistry A, 105(20), 4928-4932, (2001-05-24) |
op_relation |
https://doi.org/10.1021/jp0042009 oai:authors.library.caltech.edu:6a5jn-v5y52 eprintid:58485 resolverid:CaltechAUTHORS:20150623-154758203 |
op_rights |
info:eu-repo/semantics/closedAccess Other |
op_doi |
https://doi.org/10.1021/jp0042009 |
container_title |
The Journal of Physical Chemistry A |
container_volume |
105 |
container_issue |
20 |
container_start_page |
4928 |
op_container_end_page |
4932 |
_version_ |
1802647512898600960 |