Low-Temperature Photochemistry of Submicrometer Nitric Acid and Ammonium Nitrate Layers

Koch, Thomas; Holmes, Nicholas S.; Roddis, Tristan B.; Sodeau, John R.

doi:10.1021/jp960368b

Cited by 36 publications

(49 citation statements)

References 35 publications

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“…110 These calculations are consistent with the infrared spectra of nitric acid hydrates, which typically have strong bands in this region. [102][103][104][105] However, the bending mode of water in the 1600 cm À1 region does not change significantly on binding to nitric acid, which is consistent with our observations. [108][109][110] We therefore assign the peaks at 3300 cm À1 and 1620 cm À1 in Fig.…”

Section: à3supporting

confidence: 91%

“…Nitric acid is well known to form hydrates with water both in aqueous solution [99][100][101] and on ice. [102][103][104][105] In aqueous solution, as the concentration of nitric acid increases, the composition changes from the dissociated ions to the trihydrate and then the monohydrate, and finally pure HNO 3 . [99][100][101] On ice, the dihydrate is also observed.…”

Section: à3mentioning

confidence: 99%

“…[99][100][101] On ice, the dihydrate is also observed. [102][103][104][105] There is also theoretical evidence for nitric acid-water complexes. Ab initio calculations of the 1:1 nitric acid-water complex in the gas phase have been carried out, [108][109][110] showing that two hydrogen bonds form between HNO 3 and H 2 O with a binding energy for the complex of 9.5 kJ mol À1 .…”

Section: à3mentioning

confidence: 99%

See 2 more Smart Citations

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

Finlayson-Pitts

Wingen

Sumner

et al. 2002

Phys. Chem. Chem. Phys.

621

767

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The heterogeneous reaction of NO 2 with water on the surface of laboratory systems has been known for decades to generate HONO, a major source of OH that drives the formation of ozone and other air pollutants in urban areas and possibly in snowpacks. Previous studies have shown that the reaction is first order in NO 2 and in water vapor, and the formation of a complex between NO 2 and water at the air-water interface has been hypothesized as being the key step in the mechanism. We report data from long path FTIR studies in borosilicate glass reaction chambers of the loss of gaseous NO 2 and the formation of the products HONO, NO and N 2 O. Further FTIR studies were carried out to measure species generated on the surface during the reaction, including HNO 3 , N 2 O 4 and NO 2 + . We propose a new reaction mechanism in which we hypothesize that the symmetric form of the NO 2 dimer, N 2 O 4 , is taken up on the surface and isomerizes to the asymmetric form, ONONO 2 . The latter autoionizes to NO + NO 3 À , and it is this intermediate that reacts with water to generate HONO and surface-adsorbed HNO 3 . Nitric oxide is then generated by secondary reactions of HONO on the highly acidic surface. This new mechanism is discussed in the context of our experimental data and those of previous studies, as well as the chemistry of such intermediates as NO + and NO 2 + that is known to occur in solution. Implications for the formation of HONO both outdoors and indoors in real and simulated polluted atmospheres, as well as on airborne particles and in snowpacks, are discussed. A key aspect of this chemistry is that in the atmospheric boundary layer where human exposure occurs and many measurements of HONO and related atmospheric constituents such as ozone are made, a major substrate for this heterogeneous chemistry is the surface of buildings, roads, soils, vegetation and other materials. This area of reactions in thin films on surfaces (SURFACE ¼ Surfaces, Urban and Remote: Films As a Chemical Environment) has received relatively little attention compared to reactions in the gas and liquid phases, but in fact may be quite important in the chemistry of the boundary layer in urban areas.

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Section: à3supporting

confidence: 91%

Section: à3mentioning

confidence: 99%

Section: à3mentioning

confidence: 99%

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The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

Finlayson-Pitts

Wingen

Sumner

et al. 2002

Phys. Chem. Chem. Phys.

621

767

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“…253 The ambient temperature photolysis was estimated to generate 9.3 Gg of N 2 O per year over North America.…”

Section: 206mentioning

confidence: 99%

Introductory lecture: atmospheric chemistry in the Anthropocene

Finlayson-Pitts

2017

Faraday Discuss.

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The term “Anthropocene” was coined by Professor Paul Crutzen in 2000 to describe an unprecedented era in which anthropogenic activities are impacting planet Earth on a global scale. Greatly increased emissions into the atmosphere, reflecting the advent of the Industrial Revolution, have caused significant changes in both the lower and upper atmosphere. Atmospheric reactions of the anthropogenic emissions and of those with biogenic compounds have significant impacts on human health, visibility, climate and weather. Two activities that have had particularly large impacts on the troposphere are fossil fuel combustion and agriculture, both associated with a burgeoning population. Emissions are also changing due to alterations in land use. This paper describes some of the tropospheric chemistry associated with the Anthropocene, with emphasis on areas having large uncertainties. These include heterogeneous chemistry such as those of oxides of nitrogen and the neonicotinoid pesticides, reactions at liquid interfaces, organic oxidations and particle formation, the role of sulfur compounds in the Anthropocene and biogenic–anthropogenic interactions. A clear and quantitative understanding of the connections between emissions, reactions, deposition and atmospheric composition is central to developing appropriate cost-effective strategies for minimizing the impacts of anthropogenic activities. The evolving nature of emissions in the Anthropocene places atmospheric chemistry at the fulcrum of determining human health and welfare in the future.

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“…[12][13][14] For an unambiguous phase assignment of solid hydrates, a diffraction technique is often the method of choice. However, most studies applied to the properties of nitric acid hydrates so far have been carried out by infrared (IR) and Raman spectroscopy, 11,[15][16][17][18][19][20][21][22][23] and it is therefore important to correlate the spectra and the diffraction patterns. This task is hampered by the insufficient sensitivity of the molecular vibrations with respect to solid-phase changes s vibrational spectroscopy probes only the short-range order, that is, the direct environment of the ions and molecules (NO 3 -, H 2 O, H 3 O + , H 5 O 2 + , or H 7 O 3 + ) in question.…”

Section: Introductionmentioning

confidence: 99%

Low-Frequency Raman Spectra of Nitric Acid Hydrates

2005

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Raman spectra of solid nitric acid hydrates (NAM, alpha- and beta-NAD, alpha- and beta-NAT, and NAP) are obtained in the low-frequency region 20-175 cm(-1) where phonon bands show characteristic patterns. This fingerprint information, intimately related to the structure and symmetry of the unit cell, is well suited for observation of phase changes in solid nitric acid hydrates and allows the distinction of mixtures of different hydrate phases. The low-frequency spectra are correlated with the spectra of the respective symmetric NO stretching vibration (1000-1080 cm(-1)), with literature data, and with X-ray diffraction patterns.

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Low-Temperature Photochemistry of Submicrometer Nitric Acid and Ammonium Nitrate Layers

Cited by 36 publications

References 35 publications

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

Introductory lecture: atmospheric chemistry in the Anthropocene

Low-Frequency Raman Spectra of Nitric Acid Hydrates

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