Multiple charging of ultrafine aerosol particles by aerosol photoemission (APE)

Abstract

The high charging efficiency of aerosol photoemission (APE) for ultrafine particles (diameter < 20 nm) is demonstrated on the example of Ag. While conventional charging mechanisms do not allow attachment of more than one elementary charge per particle in this size range, up to 4-fold charging has been observed with APE. To obtain this high charge, a careful design of the charger is essential. In particular, precipitation of highly mobile particles by erratic electric fields and reneutralization by ions of opposite sign have to be avoided. High charging of particles has interesting applications for studies on interparticulate forces in agglomerates. © 1988.