Formation of condensation nuclei by ions of given polarity and age

Abstract

We have studied the production of condensation nuclei by ions of given polarity and age in mixtures of pure gas (O 2, N 2, Ar), H 2O (800 to 20,000 ppm) and SO 2 (1 ppm). When the ageing time of ions increases from 10 to 100 msec, and with constant concentration of water vapour, particle production goes through a maximum. If the ageing time is kept constant and the water concentration is varied, the same phenomenon is observed. When 100 ppm of NO is added to the mixture no further particles are produced so that it can be supposed that the reaction is due to the emission of free radicals. The mobility of ions is about 1.4 cm 2 V −1 sec −1. It can therefore be concluded that, in this case, we have H 2O-ion-impurity reactions with reaction times of about 50 msec.