Ionic equilibria and decay times of neutral water clusters in moist air

• Published in: Journal of applied physics 1981-01, Vol.52 (3), p.1584-1586
• Main Author: Carlon, Hugh R.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.329643

Ambient air humidified by boiling water can contain high concentrations (106–107/cm3) of small hydrated ions for an hour or more after water vapor generation by boiling has ceased. Recent studies have shown that these high residual concentrations probably can be explained by the decomposition of molecular complexes of water (water clusters) generated by boiling, e.g., HX(H2O)c⇋(H+H2O)c+X− where X− may be a negative ion on an electron. Infrared absorption studies show that enormous populations of neutral water clusters like HX(H2O)c exist in moist air or steam (1012–1015/cm3). Thus the lifetimes of these populations can be estimated by electrical conductivity measurements of the ions in equilibrium with them. Typical data and decay curves are presented which show mean lifetimes for neutral clusters on the order of 15 min. It is shown that these neutral clusters are present in peaked statistical distributions and, in cloud-chamber operation, can serve as condensation centers for atmospheric water vapor, probably serving as nuclei for the ’’cloudlike’’ condensation first observed by Wilson.