Particle Beam Scattering From the Vacuum–Liquid Interface

Alexander, William N.

doi:10.1016/b978-0-12-813641-6.00008-x

Cited by 7 publications

(6 citation statements)

References 151 publications

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“…, where k B is the Boltzmann constant, d is the effective cross-sectional area of a gaseous analyte molecule, T is the temperature, and p is the pressure. [17] For most volatile organic compounds, such as DNT, at ambient pressure and temperature, the mean free path is typically several tens of nanometers. [18] As the density of the gas decreases, the mean free path becomes longer as collisions occur less frequently.…”

Section: Methodsmentioning

confidence: 99%

Universal Strategy for Improving the Sensitivity of Detecting Volatile Organic Compounds by Patterned Arrays

et al. 2020

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The diffusion of target analytes is a determining factor for the sensitivity of a given gas sensor. Surface adsorption results in a low‐concentration region near the sensor surface, producing a concentration gradient perpendicular to the surface, and drives a net flux of molecules toward solid reactive reagents on the sensor surface, that is, vertical diffusion. Here, organic semiconductor supramolecules were patterned into micromeshed arrays to integrate vertical and horizontal diffusion pathways. When used as a gas sensor, these arrays have an order of magnitude higher sensitivity than traditional film‐based sensors. The sensor sensitivity ramp down with the increase in coverage density of reactive reagents, yielding two linear regions demarcated by 0.3 coverage, which are identified by the experimental results and simulations. The universal nature of template‐assisted patterning allows adjustments in the composition, size, and shape of the constituent material, including nanofibers, nanoparticles, and molecules, and thus serves to improve the sensitivity of gas sensors for detecting various volatile organic compounds.

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Section: Methodsmentioning

confidence: 99%

Universal Strategy for Improving the Sensitivity of Detecting Volatile Organic Compounds by Patterned Arrays

et al. 2020

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“…Lastly, a few more techniques for interrogating surfaces are worthy of mention: molecular beam and ion scattering, 115–117 and neutron scattering and reflectometry. 88,118,119 Techniques for measuring hygroscopicity ( i.e.…”

Section: Techniques For Measuring and Modeling Surfactants On Aerosol...mentioning

confidence: 99%

Emerging investigator series: surfactants, films, and coatings on atmospheric aerosol particles: a review

Wokosin

Schell

Faust

2022

Environ. Sci.: Atmos.

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“…We now know that molecules colliding with a surface interact in numerous ways, as summarized in recommended reviews [9][10][11][12][13][14][15][16][17][18]. During a single or multi-bounce nonreactive collision, these pathways include not only translational energy exchange but also vibrational, rotational, and electronic transitions (including spin-orbit) in the gas-phase molecule and in the surface and subsurface molecules within the collision zone.…”

Section: Condensation and Evaporation As Reverse Processesmentioning

confidence: 99%

“…Further studies show that grazing collisions (large impact parameter) transfer less energy, and thermal motions generally decrease the overall energy transfer as well. Sophisticated models of energy transfer have been developed that take into account the shape of molecules [35] and surface and their internal excitation, including the development of a "surface Newton diagram" [18,36].…”

Section: Rules Of Thumb For Gas-surface Energy Transfer and Trappingmentioning

confidence: 99%

When Liquid Rays Become Gas Rays: Can Evaporation Ever Be Non-Maxwellian?

Nathanson

2021

Molecular Beams in Physics and Chemistry

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A rare mistake by Otto Stern led to a confusion between density and flux in his first measurement of a Maxwellian speed distribution. This error reveals the key role of speed itself in Stern’s development of “the method of molecular rays”. What if the gas-phase speed distributions are not Maxwellian to begin with? The molecular beam technique so beautifully advanced by Stern can also be used to explore the speed distribution of gases evaporating from liquid microjets, a tool developed by Manfred Faubel. We employ liquid water and alkane microjets containing dissolved helium atoms to monitor the speed of evaporating He atoms into vacuum. While most dissolved gases evaporate in Maxwellian speed distributions, the He evaporation flux is super-Maxwellian, with energies up to 70% higher than the flux-weighted average energy of 2 RTliq. The explanation of this high-energy evaporation involves two beautiful concepts in physical chemistry: detailed balancing between He atom evaporation and condensation (starting with gas-surface collisions) and the potential of mean force on the He atom (starting with He atoms just below the surface). We hope that these measurements continue to fulfill Stern’s dream of the “directness and simplicity of the molecular ray method.”

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Particle Beam Scattering From the Vacuum–Liquid Interface

Cited by 7 publications

References 151 publications

Universal Strategy for Improving the Sensitivity of Detecting Volatile Organic Compounds by Patterned Arrays

Universal Strategy for Improving the Sensitivity of Detecting Volatile Organic Compounds by Patterned Arrays

Emerging investigator series: surfactants, films, and coatings on atmospheric aerosol particles: a review

When Liquid Rays Become Gas Rays: Can Evaporation Ever Be Non-Maxwellian?

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