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McGrory MR, Shepherd RH, King MD, Davidson N, Pope FD, Watson IM, Grainger RG, Jones AC, Ward AD. Mie scattering from optically levitated mixed sulfuric acid-silica core-shell aerosols: observation of core-shell morphology for atmospheric science. Phys Chem Chem Phys 2022; 24:5813-5822. [PMID: 35226003 DOI: 10.1039/d1cp04068e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sulfuric acid is shown to form a core-shell particle on a micron-sized, optically-trapped spherical silica bead. The refractive indices of the silica and sulfuric acid, along with the shell thickness and bead radius were determined by reproducing Mie scattered optical white light as a function of wavelength in Mie spectroscopy. Micron-sized silica aerosols (silica beads were used as a proxy for atmospheric silica minerals) were levitated in a mist of sulfuric acid particles; continuous collection of Mie spectra throughout the collision of sulfuric acid aerosols with the optically trapped silica aerosol demonstrated that the resulting aerosol particle had a core-shell morphology. Contrastingly, the collision of aqueous sulfuric acid aerosols with optically trapped polystyrene aerosol resulted in a partially coated system. The light scattering from the optically levitated aerosols was successfully modelled to determine the diameter of the core aerosol (±0.003 μm), the shell thickness (±0.0003 μm) and the refractive index (±0.007). The experiment demonstrated that the presence of a thin film rapidly changed the light scattering of the original aerosol. When a 1.964 μm diameter silica aerosol was covered with a film of sulfuric acid 0.287 μm thick, the wavelength dependent Mie peak positions resembled sulfuric acid. Thus mineral aerosol advected into the stratosphere would likely be coated with sulfuric acid, with a core-shell morphology, and its light scattering properties would be effectively indistinguishable from a homogenous sulfuric acid aerosol if the film thickness was greater than a few 100 s of nm for UV-visible wavelengths.
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Affiliation(s)
- Megan R McGrory
- Central Laser Facility, Research Complex, STFC Rutherford Appleton Laboratory, Oxford, OX11 0FA, UK. .,Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK
| | - Rosalie H Shepherd
- Central Laser Facility, Research Complex, STFC Rutherford Appleton Laboratory, Oxford, OX11 0FA, UK. .,Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK
| | - Martin D King
- Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK
| | - Nicholas Davidson
- School of Geography, Earth & Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Francis D Pope
- School of Geography, Earth & Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - I Matthew Watson
- School of Earth Science, University of Bristol, Wills Memorial Building, Bristol, BS8 1RJ, UK
| | - Roy G Grainger
- National Centre for Earth Observation, Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK
| | - Anthony C Jones
- Met Office, Fitzroy Road, Exeter, EX1 3PB, UK.,College of Engineering Maths and Physical Sciences, University of Exeter, Exeter, EX4 4PY, UK
| | - Andrew D Ward
- Central Laser Facility, Research Complex, STFC Rutherford Appleton Laboratory, Oxford, OX11 0FA, UK.
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Bain A, Preston TC. The wavelength-dependent optical properties of weakly absorbing aqueous aerosol particles. Chem Commun (Camb) 2020; 56:8928-8931. [DOI: 10.1039/d0cc02737e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A model for calculating the wavelength-dependent refractive index of multicomponent mixtures is presented and applied to aqueous systems in the atmosphere and oceans.
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Affiliation(s)
- Alison Bain
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry
- McGill University
- Montreal
- Canada
| | - Thomas C. Preston
- Department of Atmospheric and Oceanic Sciences and Department of Chemistry
- McGill University
- Montreal
- Canada
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Verdes M, Paniagua M. Facet shapes and thermo-stabilities of H₂SO₄•HNO₃ hydrates involved in polar stratospheric clouds. J Mol Model 2015; 21:238. [PMID: 26287119 DOI: 10.1007/s00894-015-2782-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 07/31/2015] [Indexed: 11/24/2022]
Abstract
The nucleation, ice crystal shapes and thermodynamic stability of polar stratospheric clouds particles are interesting concerns owing to their implication in the ozone layer destruction. Some of these particles are formed by conformers of H2O, HNO3, and H2SO4. We carried out calculations using density functional theory (DFT) to obtain optimized structures. Several stable trimers are achieved -divided in two groups, one with HNO3 moiety, second with H2SO4 moiety- after pre-optimization at B3LYP/6-31G and subsequently optimization at B3LYP/aug-cc-pVTZ level of theory. For both most stable conformers five H2O molecules are added to their optimized trimers to calculate hydrated geometries. The OH stretching harmonic frequencies are provided for all aggregates. The zero-point energy correction (ZEPC), relative electronic energies (∆E), relative reaction Gibbs free energies ∆(∆G)k-relative, and cooling constant (K cooling ) are reported at three temperatures: 188 K, 195 K, and 210 K. Shapes given in our calculations are compared with various experimental shapes as well as comparisons with their thermo-stabilities.
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Affiliation(s)
- Marian Verdes
- Departamento de Química Física Aplicada, Facultad de Ciencias, C-14, Universidad Autónoma de Madrid, Cantoblanco, E-28049, Madrid, Spain,
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Moussa SG, Kuo MH, McNeill VF. Nitric acid-induced surface disordering on ice. Phys Chem Chem Phys 2013; 15:10989-95. [DOI: 10.1039/c3cp50487e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Benassi P, Nardone M, Giugni A. Sound dispersion and attenuation in concentrated H2SO4 by visible and ultraviolet Brillouin spectroscopy. J Chem Phys 2011; 135:034503. [PMID: 21787009 DOI: 10.1063/1.3609975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The acoustic properties of highly concentrated H(2)SO(4) are investigated performing visible and ultraviolet Brillouin scattering measurements. We analyzed the isotropic and anisotropic spectra of this molecular liquid in a wide temperature and exchanged wavector range in order to study the evolution of its sound velocity and viscosity. This allows us to extract the parameters required to describe its viscoelastic relaxation behavior. We found that the behavior of the hydrodynamic parameters of this molecular liquid shares some similarities with that of water indicating a rather high increase of sound velocity if compared to that measured by ultrasonics.
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Affiliation(s)
- P Benassi
- Dipartimento di Fisica and CNISM-CNR, Università de L'Aquila, via Vetoio, 67100 Coppito, Italy
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Jumelet J, Bekki S, David C, Keckhut P, Baumgarten G. Size distribution time series of a polar stratospheric cloud observed above Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) (69°N) and analyzed from multiwavelength lidar measurements during winter 2005. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd010119] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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7
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Wagner R, Benz S, Bunz H, Möhler O, Saathoff H, Schnaiter M, Leisner T, Ebert V. Infrared Optical Constants of Highly Diluted Sulfuric Acid Solution Droplets at Cirrus Temperatures. J Phys Chem A 2008; 112:11661-76. [DOI: 10.1021/jp8066102] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Robert Wagner
- Forschungszentrum Karlsruhe, Institute of Meteorology and Climate Research (IMK-AAF), Karlsruhe, Germany
| | - Stefan Benz
- Forschungszentrum Karlsruhe, Institute of Meteorology and Climate Research (IMK-AAF), Karlsruhe, Germany
| | - Helmut Bunz
- Forschungszentrum Karlsruhe, Institute of Meteorology and Climate Research (IMK-AAF), Karlsruhe, Germany
| | - Ottmar Möhler
- Forschungszentrum Karlsruhe, Institute of Meteorology and Climate Research (IMK-AAF), Karlsruhe, Germany
| | - Harald Saathoff
- Forschungszentrum Karlsruhe, Institute of Meteorology and Climate Research (IMK-AAF), Karlsruhe, Germany
| | - Martin Schnaiter
- Forschungszentrum Karlsruhe, Institute of Meteorology and Climate Research (IMK-AAF), Karlsruhe, Germany
| | - Thomas Leisner
- Forschungszentrum Karlsruhe, Institute of Meteorology and Climate Research (IMK-AAF), Karlsruhe, Germany
| | - Volker Ebert
- University of Heidelberg, Physical Chemistry Institute, Heidelberg, Germany
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Steele HM, Eldering A, Lumpe JD. Simulations of the accuracy in retrieving stratospheric aerosol effective radius, composition, and loading from infrared spectral transmission measurements. APPLIED OPTICS 2006; 45:2014-27. [PMID: 16579572 DOI: 10.1364/ao.45.002014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We examine the extent to which three physical aerosol parameters--effective radius, composition (sulfate weight percent), and total volume-can be determined from infrared transmission spectra. Using simulated transmission data over the range 800-4750 cm(-1) (12.5-2.1 microm) and errors taken from the infrared spectral measurements of the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument, we use optimal estimation to recover these aerosol parameters. Uncertainties in these are examined as a function of the size, composition, and loading of stratospheric aerosols and of the spectral range employed. Using the entire spectral range above, we retrieve all three parameters with a precision to within 3% if the size distribution form is known. Additional errors result, however, from an uncertainty in the size distribution width. These are small (only a few percent) for composition and total volume but are substantial (as much as 50%) for effective radius. Errors also increase substantially when the spectral range is reduced. The retrieved effective radius can have an error of 100% or greater for typical stratospheric aerosol sizes when the spectral range is restricted to the lower wavenumber part of the range. For good accuracy in effective radius, the spectral range must extend beyond approximately 3000 cm(-1). Composition and total volume are less sensitive to the spectral range than effective radius. These simulations were carried out with modeled data to test the potential accuracy of stratospheric sulfate aerosol retrievals from the Atmospheric Chemistry Experiment (ACE). Because of the limitations that result from the use of simulated data, we have tested our retrieval algorithm using ATMOS spectra in different filter regions and present here the aerosol parameters obtained.
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Affiliation(s)
- Helen M Steele
- Department of Geography, California State University, Northridge, 18111 Nordhoff Street, Northridge, California 91330-8249, USA.
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Wagner R, Naumann KH, Mangold A, Möhler O, Saathoff H, Schurath U. Aerosol Chamber Study of Optical Constants and N2O5 Uptake on Supercooled H2SO4/H2O/HNO3 Solution Droplets at Polar Stratospheric Cloud Temperatures. J Phys Chem A 2005; 109:8140-8. [PMID: 16834200 DOI: 10.1021/jp0513364] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanism of the formation of supercooled ternary H(2)SO(4)/H(2)O/HNO(3) solution (STS) droplets in the polar winter stratosphere, i.e., the uptake of nitric acid and water onto background sulfate aerosols at T < 195 K, was successfully mimicked during a simulation experiment at the large coolable aerosol chamber AIDA of Forschungszentrum Karlsruhe. Supercooled sulfuric acid droplets, acting as background aerosol, were added to the cooled AIDA vessel at T = 193.6 K, followed by the addition of ozone and nitrogen dioxide. N(2)O(5), the product of the gas phase reaction between O(3) and NO(2), was then hydrolyzed in the liquid phase with an uptake coefficient gamma(N(2)O(5)). From this experiment, a series of FTIR extinction spectra of STS droplets was obtained, covering a broad range of different STS compositions. This infrared spectra sequence was used for a quantitative test of the accuracy of published infrared optical constants for STS aerosols, needed, for example, as input in remote sensing applications. The present findings indicate that the implementation of a mixing rule approach, i.e., calculating the refractive indices of ternary H(2)SO(4)/H(2)O/HNO(3) solution droplets based on accurate reference data sets for the two binary H(2)SO(4)/H(2)O and HNO(3)/H(2)O systems, is justified. Additional model calculations revealed that the uptake coefficient gamma(N(2)O(5)) on STS aerosols strongly decreases with increasing nitrate concentration in the particles, demonstrating that this so-called nitrate effect, already well-established from uptake experiments conducted at room temperature, is also dominant at stratospheric temperatures.
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Affiliation(s)
- Robert Wagner
- Forschungszentrum Karlsruhe, Institute of Meteorology and Climate Research (IMK-AAF), Karlsruhe, Germany.
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Lund Myhre CE, Grothe H, Gola AA, Nielsen CJ. Optical Constants of HNO3/H2O and H2SO4/HNO3/H2O at Low Temperatures in the Infrared Region. J Phys Chem A 2005; 109:7166-71. [PMID: 16834080 DOI: 10.1021/jp0508406] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The complex index of refraction of liquid HNO3/H2O and H2SO4/HNO3/H2O has been obtained at different temperatures and acid concentrations. FT-IR specular reflectance spectra were obtained for 30, 54, and 64 wt % aqueous HNO3 and for four different H2SO4/HNO3/H2O mixtures in the temperature region from 293 to 183 K. The complex index of refraction was obtained from the reflectance spectra with the Kramers-Kronig transformation. The optical constants of the binary and ternary mixtures vary with the acid concentration and the temperature. The results demonstrate that vibrational bands originating from the sulfate species are more sensitive to changes in temperature than the bands originating from vibrations in the nitrate species; only minor changes in the nitrate vibrational bands are observed as the temperature decreases below 248 K.
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Affiliation(s)
- C E Lund Myhre
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0372 Oslo, Norway
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Brooks SD. Polar stratospheric clouds during SOLVE/THESEO: Comparison of lidar observations with in situ measurements. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jd003463] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Luo BP. Extreme NAT supersaturations in mountain wave ice PSCs: A clue to NAT formation. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002jd003104] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Voigt C. In situ mountain-wave polar stratospheric cloud measurements: Implications for nitric acid trihydrate formation. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2001jd001185] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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