Absorption of millimeter to submillimeter waves by atmospheric water molecules
Abstract
Using the values of the rotational molecular parameters (including cencrifugal distortion terms) of the H2 16O molecule, which can explain 12 observed transitions below 800 GHz, all rotational energy levels with normalized Boltzmann factors larger than 5×10-8 at 300°K are calculated. Probabilities of all possible electric dipole transitions among these states, 2277 lines, are calculated using the eigenfunctions thus obtained, and the permanent electric dipole moment of 1.8546 Debye. Assuming the single and full Lorentzian line forms, we calculated the absorption coefficient for millimeter to submillimeter region. Our result, using the single term Lorentzian line form, agrees quite well with experiment for 1 Torr of water vapor in 760 Torr air at 300°K.
- Publication:
-
International Journal of Infrared and Millimeter Waves
- Pub Date:
- May 1982
- DOI:
- 10.1007/BF01006251
- Bibcode:
- 1982IJIMW...3..379M
- Keywords:
-
- Atmospheric Attenuation;
- Microwave Attenuation;
- Millimeter Waves;
- Molecular Absorption;
- Submillimeter Waves;
- Water Vapor;
- Absorptivity;
- Dipole Moments;
- Electric Dipoles;
- Infrared Absorption;
- Line Spectra;
- Molecular Energy Levels;
- Molecular Rotation;
- Geophysics;
- water vapor;
- millimeter waves;
- submillimeter waves;
- excess absorption;
- Lorentzian line form;
- window regions