Wall-collision line broadening of molecular oxygen within nanoporous materials

Xu, Cuilian; Lewander, Märta; Andersson‐Engels, Stefan; Adolfsson, Erik; Svensson, Tomas; Svanberg, Sune

doi:10.1103/physreva.84.042705

Cited by 23 publications

(7 citation statements)

References 32 publications

(41 reference statements)

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“…However, not until around 2010 did measurements clearly demonstrate these confinement effects [645][646][647]. These experiments showed that lines of H 2 O vapor inside an aerogel sample [645] and of O 2 gas inside ceramics [647] are significantly broader than those observed for the same pressures and species under unconfined conditions. This is also shown in [648,649] and Fig.…”

Section: Probing Confined Gasesmentioning

confidence: 77%

“…It was predicted many years ago that the (tight) confinement of molecular gases inside enclosures where they are free to move (and not adsorbed) induces a modification of the shapes of absorption lines through the increased contribution of molecule-surface collisions [643,644]. However, not until around 2010 did measurements clearly demonstrate these confinement effects [645][646][647]. These experiments showed that lines of H 2 O vapor inside an aerogel sample [645] and of O 2 gas inside ceramics [647] are significantly broader than those observed for the same pressures and species under unconfined conditions.…”

Section: Probing Confined Gasesmentioning

confidence: 99%

See 1 more Smart Citation

Recent advances in collisional effects on spectra of molecular gases and their practical consequences

Hartmann

Tran

Armante

et al. 2018

Journal of Quantitative Spectroscopy and Radiative Transfer

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Section: Probing Confined Gasesmentioning

confidence: 77%

Section: Probing Confined Gasesmentioning

confidence: 99%

Recent advances in collisional effects on spectra of molecular gases and their practical consequences

Hartmann

Tran

Armante

et al. 2018

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…Since the free mean path of molecules in ambient air is about 60 nm, this means, that wall‐collision broadening would occur in nano‐porous materials. Such effects, potentially useful for non‐intrusive determination of pore‐size distributions, have been predicted and observed in nano‐porous ceramics .…”

Section: Basic Priniples Of Gas In Scattering Media Absorption Spectrmentioning

confidence: 98%

Gas in scattering media absorption spectroscopy – from basic studies to biomedical applications

Svanberg

2013

Laser & Photonics Reviews

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The recently introduced Gas in Scattering Media Absorption Spectroscopy (GASMAS) technique provides novel possibilities for analysis in biophotonics. Free gas in pores or cavities is monitored with narrow-band laser radiation, which can discern the gas absorptive imprints which are typically several orders of magnitude more narrow than the features of the surrounding tissue through which the diffusely scattered light emerges to the detector. Important gases monitored are oxygen and water vapour. Applications include diagnosis of human sinus cavities and surveillance of neonatal children, but also characterization of food-stuffs, food packages and pharmaceutical preparations. Non-biological applications include the study of construction materials such as wood, polystyrene foams and ceramics. For nano-porous materials, information on the pore sizes can be obtained from observed line broadening. Apart from concentration measurements, the GASMAS technique also allows the study of gas transport and diffusion, and pressure and temperature information can also be obtained.

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“…Since the emerging light is weak and nonlocalized, a large‐area detector combined with extremely sensitive detection electronics is needed to pick up the faint gas imprints [10]. This type of spectroscopy, denoted gas in scattering media absorption spectroscopy (GASMAS), has since found a lot of applications in many areas [11, 12], regarding, for example, materials [13–15], pore‐size analysis [16–18], food packages [19, 20], fruits [21, 22], pharmaceuticals [23] and medical diagnostics [5, 11].…”

Section: Introductionmentioning

confidence: 99%

Gas in scattering media absorption spectroscopy on small and large scales: Toward the extension of lung spectroscopic monitoring to adults

Lin

Lundin

Svanberg

et al. 2021

Transl Biophotonics

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Numerous natural materials are porous, contain free gas and are scattering light strongly. Scattering brings about a strong trapping of light and an associated prolonged transit time for photons through a medium. In contrast to the matrix materials, gas enclosures require very narrowband laser radiation for probing. We have in the present study used the gas in scattering media absorption spectroscopy method to study free oxygen in thin (cm) samples utilizing a tunable diode laser, while a pulsed dye laser was employed in corresponding measurements on larger samples, up to the meter scale. Time‐resolved spectroscopy was in both cases used to assess the temporal distribution of the detected photons, mapping the path lengths through the media, which ranged between few centimeters up to 100 m. This study explores the feasibility to extend recent successful monitoring of gases in neonatal infant lungs to the case of larger children or even adults, which could have very important applications, for example, in ventilator setting optimization for severely ill patients, suffering, for example, from SARS‐CoV‐2. The conclusion of our work is that this goal most realistically can be reached by applying intratracheal laser light illumination at the 1 W power level, employing a tapered amplifier, injected with a distributed feedback diode‐laser oscillator output and combined with wavelength‐modulation spectroscopy.

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Wall-collision line broadening of molecular oxygen within nanoporous materials

Cited by 23 publications

References 32 publications

Recent advances in collisional effects on spectra of molecular gases and their practical consequences

Recent advances in collisional effects on spectra of molecular gases and their practical consequences

Gas in scattering media absorption spectroscopy – from basic studies to biomedical applications

Gas in scattering media absorption spectroscopy on small and large scales: Toward the extension of lung spectroscopic monitoring to adults

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