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Updated: Jul 11, 2026

Near-Infrared Temperature Measurement Technique for Water Surrounding an Induction-heated Small Magnetic Sphere
Published on: April 30, 2018
Atmospheric detection of water dimers via near-infrared absorption
K Pfeilsticker1, A Lotter, C Peters
1Institut für Umweltphysik, INF 229, University of Heidelberg, D-69120 Heidelberg, Germany.
Abstract:
Weakly bonded pairs of water molecules (H2O)2, or water dimers (WDs), may play an important role in photochemistry and climate, but the overlap of most of its spectral features with the water monomer (WM) has made detection difficult. We report on WD absorption measurements by means of atmospheric long-path (18.34 kilometers) differential optical absorption spectroscopy of the near-infrared OH stretching mode 0>f 4>b overtone transition predicted to be located near 746 nanometers. Our observation is in reasonable agreement with the known thermochemistry, calculated and measured structure, and spectroscopy (band strength, shape, and width) of the WD. The observation implies that the WD 0>f 4>b band is located at 749.5 nanometers, with a full width at half maximum of approximately 19.4 wave numbers, and that its band strength ranges between 1.23 x 10(-22) and 5.25 x 10(-22) centimeters per molecule.
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