Experimental study of vapor nucleation on ions

Abstract

The ion-induced nucleation of six vapors (carbon tetrachloride, chloroform, o-xylene, methanol, ethanol, and water) has been investigated in a thermal diffusion cloud chamber using helium as a carrier gas. High densities of ions were produced in the chamber by use of «-sources and separation of positive and negative charges has been achieved by use of an electric field. Experiments have been conducted such that nucleation occurred in the presence or absence of an electric field in the nucleation zone. When the electric field was present, the so-called sign effect was observed, while no effect occurred in the absence of the electric field.

Nucleation of Water and Methanol Droplets on Cations and Anions: The Sign Preference

“…However, the asymmetry between water-positive-ion and waternegative-ion interactions can lead to ion-sign preference in condensation of water. This phenomenon is known as the sign preference [6][7][8][9][10][11][12][13].…”

“…He found negative ions were more effective to produce a rain of water droplets in the presence of an external electric field. Ninety years later Rabeony and Mirabel reported that the sign preference of water was not detectable [9] if the external electric field was not applied. To date, the existence (or disappearance) of the sign preference in the condensation of water without the presence of an external electric field is still not fully confirmed (see Ref.…”

Effects of external electric field on the interfacial properties of weakly dipolar fluid

“…Examples include ion-induced nucleation [1][2][3][4][5][6][7][8][9][10] and nucleation in a uniform electric field. [11][12][13][14][15][16] The classical theory of nucleation predicts that the barrier height to nucleation is proportional to the cube of the surface tension in the absence of electric field.…”

Ion-induced nucleation: A density functional approach

“…[1][2][3][4][5][6] The phenomenon of ion-induced nucleation plays an important role in atmospheric condensation, particularly in the ionosphere. While both positive and negative ions increase the nucleation rate, a variety of substances exhibit a dependence of the nucleation rate on the sign of the ion.…”

“…While both positive and negative ions increase the nucleation rate, a variety of substances exhibit a dependence of the nucleation rate on the sign of the ion. [1][2][3][4][5][6] No theory currently exists that is capable of predicting this sign dependence.…”