(Russian Original Vol. 58, No. 4, April, 2015)
This work is devoted to estimation of the additional absorption of millimeter and submillimeter wavelengths in water vapor arising from collisional interaction of molecules due to the induced dipole moment. Absorption is modeled on the basis of ab initio data on the magnitude of the water molecule dipole moment at high densities, and common knowledge of the water vapor absorption spectrum. Using the model developed, we obtained a simple analytical expression for the absorption coefficient as a function of temperature, pressure, and frequency. Comparison of the results with known experimental data leads to the conclusion that in the range of pressures and temperatures typical of water vapor in the Earth’s atmosphere this type of absorption is negligible compared with the absorption arising due to association or dimerization of the water vapor molecules.
Russian version (Известия ВУЗов, Радиофизика )
Radiophysics and Quantum Electronics reports on topics such as: radio astronomy; plasma astrophysics; ionospheric, atmospheric and oceanic physics; radiowave propagation; quantum radiophysics; physics of oscillations and waves; physics of plasmas; statistical radiophysics; electrodynamics; vacuum and plasma electronics; acoustics; and solid-state electronics.
Radiophysics and Quantum Electronics is a translation of the peer-reviewed Russian journal Izvestiya VUZ. Radiofizika, published by the Radiophysical Research Institute and N.I. Lobachevsky State University at Nizhnii Novgorod, Russia.
English (Science - Nauka)
The paper presents results of extensive experimental study of the water related continuum absorption in a mixture of water vapor and nitrogen in 107–143 GHz frequency range at accurately controlled laboratory conditions. Resonator spectrometer and modified method of measurement that minimizes systematic errors related to water adsorption were employed. It allowed investigation in temperature range 261–328 K, including a first-time laboratory study of the continuum at temperatures below freezing. Coefficients of the common empirical parameterization of the continuum including self (H2O–H2O) and foreign (H2O–N2) parts are derived and compared with results of the most known previous experimental and theoretical studies demonstrating very good qualitative and in some cases quantitative agreement. Dominating types of intermolecular interactions leading to the observed continuum are discussed.
