Open AccessLaser absorption spectroscopy of water vapor confined in nanoporous alumina: wall collision line broadening and gas diffusion dynamics
Author(s) -
Tomas Svensson,
Märta Lewander,
Sune Svanberg
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.016460
Subject(s) - tunable diode laser absorption spectroscopy , water vapor , materials science , spectroscopy , nanoporous , absorption (acoustics) , optics , absorption spectroscopy , diffusion , laser , photon diffusion , scattering , line (geometry) , molecular physics , analytical chemistry (journal) , tunable laser , chemistry , nanotechnology , physics , organic chemistry , layer (electronics) , quantum mechanics , composite material , thermodynamics , geometry , mathematics , chromatography
We demonstrate high-resolution tunable diode laser absorption spectroscopy (TDLAS) of water vapor confined in nanoporous alumina. Strong multiple light scattering results in long photon pathlengths (1 m through a 6 mm sample). We report on strong line broadening due to frequent wall collisions (gas-surface interactions). For the water vapor line at 935.685 nm, the HWHM of confined molecules are about 4.3 GHz as compared to 2.9 GHz for free molecules (atmospheric pressure). Gas diffusion is also investigated, and in contrast to molecular oxygen (that moves rapidly in and out of the alumina), the exchange of water vapor is found very slow.