Ambient Thin Film Water on Insulator Surfaces

Ewing, George E.

doi:10.1021/cr040369x

Cited by 218 publications

(193 citation statements)

References 117 publications

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“…In the range of 50-75% RH, below the DRH of NaNO 3 , NO 2 continues to be generated but at a smaller rate. While the salt is solid under these conditions, it holds significant amounts of surface-adsorbed water [101][102][103][104] which increases ion mobility at the interface and provides some liquid-like character to the surface. These results for NaNO 3 suggest that R NO 2 from KNO 3 would be higher if photolysis experiments were conducted 5% above the DRH rather than 7% below, and hence the data in Fig.…”

Section: Resultsmentioning

confidence: 99%

The effect of cations on NO₂ production from the photolysis of aqueous thin water films of nitrate salts

Richards-Henderson

Anderson

Anastasio

et al. 2015

Phys. Chem. Chem. Phys.

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The photochemistry of nitrate ions in bulk aqueous solution is well known, yet recent evidence suggests that the photolysis of nitrate may be more efficient at the air-water interface. Whether and how this surface enhancement is altered by the presence of different cations is not known. In the present studies, thin aqueous films of nitrate salts with different cations were deposited on the walls of a Teflon chamber and irradiated with 311 nm light at 298 K. The films were generated by nebulizing aqueous 0.5 M solutions of the nitrate salts and the generation of gas-phase NO 2 was monitored with time. The nitrate salts fall into three groups based on their observed rate of NO 2 formation (R NO 2 ): (1) RbNO 3 and KNO 3 , which readily produce NO 2 (R NO 2 4 3 ppb min À1 ), (2) Ca(NO 3 ) 2 , which produces NO 2 more slowly (R NO 2 o 1 ppb min À1 ), and (3) Mg(NO 3 ) 2 and NaNO 3 , which lie between the other two groups. Neither differences in the UV-visible spectra of the nitrate salt solutions nor the results of bulk-phase photolysis studies could explain the differences in the rates of NO 2 production between these three groups. These experimental results, combined with some insights from previous molecular dynamic simulations and vibrational sum frequency generation studies, show that cations may impact the concentration of nitrate ions in the interface region, thereby directly impacting the effective quantum yields for nitrate ions.

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Section: Resultsmentioning

confidence: 99%

The effect of cations on NO₂ production from the photolysis of aqueous thin water films of nitrate salts

Richards-Henderson

Anderson

Anastasio

et al. 2015

Phys. Chem. Chem. Phys.

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“…This structure is similar to that of ordinary I h ice, except that the adsorbed bilayer is slightly distorted due to the lattice mismatch with the NaCl(100) surface. 58 The experimental findings of the well-ordered icelike c(2 × 4) bilayer structure are supported by theoretical approaches including molecular dynamics calculations by Wassermann et al 55 and Meyer et al, 56 as well as density functional calculations from Park et al 57 Considering that the binding energy of H 2 O molecules to an alkali halide crystal is on the order of 0.4 eV, 59 it is reasonable to observe higher dissipation on sample areas where this water layer is expelled from the surface. Hydrodynamic friction forces could also contribute to energy dissipation that occurs when the water layer that separates tip and sample is expelled and drawn in by the oscillating tip.…”

Section: B Effect Of Hydration Layer On Dampingmentioning

confidence: 87%

Optimizing atomic resolution of force microscopy in ambient conditions

2013

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Ambient operation poses a challenge to atomic force microscopy because in contrast to operation in vacuum or liquid environments, the cantilever dynamics change dramatically from oscillating in air to oscillating in a hydration layer when probing the sample. We demonstrate atomic resolution by imaging of the KBr(001) surface in ambient conditions by frequency-modulation atomic force microscopy with a cantilever based on a quartz tuning fork (qPlus sensor) and analyze both long-and short-range contributions to the damping. The thickness of the hydration layer increases with relative humidity; thus varying humidity enables us to study the influence of the hydration layer thickness on cantilever damping. Starting with measurements of damping versus amplitude, we analyzed the signal and the noise characteristics at the atomic scale. We then determined the optimal amplitude which enabled us to acquire high-quality atomically resolved images.

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“…Exposure to particulate matter (PM) has adverse effects on cardiopulmonary health (Pope and Dockery, 2006). Thin film water is ubiquitous and can cover the surfaces of many materials (Ewing, 2006). Earlier work has reported the formation of a monolayer of adsorbed water on the surface of solid AS at 60 % relative humidity (RH) (Romakkaniemi et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Electrospray surface-enhanced Raman spectroscopy (ES-SERS) for probing surface chemical compositions of atmospherically relevant particles

Gen

Chan

2017

Atmos. Chem. Phys.

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Abstract. We present electrospray surface-enhanced Raman spectroscopy (ES-SERS) as a new approach to measuring the surface chemical compositions of atmospherically relevant particles. The surface-sensitive SERS is realized by electrospraying Ag nanoparticle aerosols over analyte particles. Spectral features at v(SO Enhanced spectra of the solid AS and AS / SA particles revealed the formation of surface-adsorbed water on their surfaces at 60 % relative humidity. These observations of surface aqueous sulfate and adsorbed water demonstrate a possible role of surface-adsorbed water in facilitating the dissolution of sulfate from the bulk phase into its water layer(s). Submicron ambient aerosol particles collected in Hong Kong exhibited non-enhanced features of black carbon and enhanced features of sulfate and organic matter (carbonyl group), indicating an enrichment of sulfate and organic matter on the particle surface.

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Ambient Thin Film Water on Insulator Surfaces

Abstract: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Cited by 218 publications

References 117 publications

The effect of cations on NO₂ production from the photolysis of aqueous thin water films of nitrate salts

The effect of cations on NO₂ production from the photolysis of aqueous thin water films of nitrate salts

Optimizing atomic resolution of force microscopy in ambient conditions

Electrospray surface-enhanced Raman spectroscopy (ES-SERS) for probing surface chemical compositions of atmospherically relevant particles

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Ambient Thin Film Water on Insulator Surfaces

Abstract: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Cited by 218 publications

References 117 publications

The effect of cations on NO2 production from the photolysis of aqueous thin water films of nitrate salts

The effect of cations on NO2 production from the photolysis of aqueous thin water films of nitrate salts

Optimizing atomic resolution of force microscopy in ambient conditions

Electrospray surface-enhanced Raman spectroscopy (ES-SERS) for probing surface chemical compositions of atmospherically relevant particles

Contact Info

Product

Resources

About

The effect of cations on NO₂ production from the photolysis of aqueous thin water films of nitrate salts

The effect of cations on NO₂ production from the photolysis of aqueous thin water films of nitrate salts