Infrared absorption by molecular clusters in water vapor

Abstract

New findings concerning clusters of water molecules in water vapor and in moist air are combined with observations from classical cloud physics to show that many discrepancies can be reconciled by the existence of enormous equilibrium populations ofiarge neutral water clusters in the vapor state. These water clusters are believed to be those "nuclei"responsible for the "cloudlike" condensation first described by Wilson at supersaturations of 4-5. They absorb electromagnetic radiation at infrared and longer wavelengths, and are believed to be responsible for the atmospheric infrared continuum absorption.

Thermodynamic stability of finely dispersed Na+Cl−(H2O) n aerosol particles in water vapor

“…The concentration of ion pairs seven to eight orders higher than the concentration of unpaired ions is also confirmed by the spectrometric measurements [4,5,[59][60][61]. Moreover, the solution shows an even stronger pre dominance of ion pairs than the abnormally high val ues obtained in the experiments, because the solution has been obtained only for and ions.…”

“…The substitution of the parame ters for the barrier of the mean force potential calcu lated by the Monte Carlo method into this equation has resulted in a solution that shows the slow accumu lation of solvent separated ion pairs to abnormally high concentrations. This result explains the experi mental spectrometric findings [4,5] and the data of radar probing [62][63][64]. The stationary solution of the kinetic equation has shown that the relative fraction of solvent separated ion pairs retained in clusters grows in proportion to the concentration of unpaired ions that arise under the action of an internal radiation 3 …”

“…The disintegration into ion pairs leads to the stabilization of a large population of electrically neutral water clusters in the upper atmo sphere [59][60][61]. These clusters cause the appearance of an abnormally intense absorption band of down streams in the IR region of electromagnetic radiation [4,5] at frequencies corresponding to vibrations of hydrogen bonds.…”

“…Electric charges present in the natural atmosphere govern its electrical properties [1][2][3] and essentially affect its optical characteristics [4,5]. Diverse forms of atmospheric electricity-from the global electric cur rent [6] to streak lightning [7,8] and fireball [9][10][11][12]depend on the presence of free charges in the atmo sphere [13].…”

Theory of the water vapor continuum and validations

“…As a result of this extensive work, there is nearly unanimous agreement on the density depen-0169-8095/95/S09.50 © 1995 Elsevier Science B.V. All rights reserved SSDI0169-8095(94)00028-0 dence (quadratic), general agreement on the temperature dependence (strong, negative, at least in the 8-13 fim window for atmospheric temperatures), but considerable disagreement as to the magnitude and physical mechanism responsible for the absorption. Water dimers (Penner and Varanasi, 1967), polymers (Carlon, 1981), collision-induced absorption (Birnbaum, 1985), and the superposition of the far wings of collisionally broadened allowed dipole lines (Elsasser, 1938) have all been suggested as possible sources of the water continuum. While the first two mechanisms are undoubtedly present and contribute to the absorption in the atmosphere (in varying amounts in the different spectral regions), there is increasing evidence to believe that they are not the primary mechanism.…”