title: Three-body collisions as a particle formation mechanism in silver nanoparticle synthesis.
abstract: Silver nanoparticles were prepared in a tubular flow reactor using an evaporation-condensation technique. The size distribution of the particles was measured using standard aerosol instruments and electron microscopy. A comparison with results obtained by a discrete population balance model with molecule-by-molecule resolution suggest that the particles probably nucleate kinetically through a dimerization process instead of a thermodynamic pathway over a free energy barrier, as is typically described by classical nucleation theory. Furthermore, the kinetic rate of dimerization seems to be accompanied by a correction term, associated with the requirement of energy and momentum conservation in molecule-molecule collisions. This energy conservation requires the presence of three-body collisions at the very initial step of particle formation.
authors.affiliation: University of Helsinki, Department of Physical Sciences, PO Box 64, 00014 Helsinki, Finland. kari.lehtinen@helsinki.fi
authors.forename: Kari E J
authors.initials: KE
authors.lastname: Lehtinen
authors.forename: Ulrika
authors.initials: U
authors.lastname: Backman
authors.forename: Jorma K
authors.initials: JK
authors.lastname: Jokiniemi
authors.forename: Markku
authors.initials: M
authors.lastname: Kulmala