After the invention of molecular-beam techniques, both experimentalists and theoreticians have been able to study "free" gas-phase clusters. Production of clusters in a molecular beam generally requires initial vaporization of an atomic or molecular source, followed by cooling and condensation of the resulting fragments via nucleation, which may involve the capture of single atoms or the coalescence of larger clusters. Metal clusters are among the first in which new properties have been found because of the effects on a nanometer scale1,2. In the last years, bimetallic nanoclusters have become of greater interest than monometallic ones, both technologically and scientifically. Very recently, we have proposed a new way of forming bimetallic nanoclusters of various structures and chemical composition by means of collision of two metal clusters of different nature3. Bimetallic nanoclusters of core-shell (Pt–Au, Co-Ag), alloyed (Pd–Au, Cu-Au), and three-shell onionlike Cu–Ag structures were found after collision of two clusters with a given initial velocity. While the nature of the emerging nanostructure (core shell, alloy, and onionlike) is determined by the chemical nature of the colliding clusters, the initial kinetic energy is an important control parameter. Structural and dynamic properties are evaluated from atom dynamics and Monte Carlo simulations.1,2. In the last years, bimetallic nanoclusters have become of greater interest than monometallic ones, both technologically and scientifically. Very recently, we have proposed a new way of forming bimetallic nanoclusters of various structures and chemical composition by means of collision of two metal clusters of different nature3. Bimetallic nanoclusters of core-shell (Pt–Au, Co-Ag), alloyed (Pd–Au, Cu-Au), and three-shell onionlike Cu–Ag structures were found after collision of two clusters with a given initial velocity. While the nature of the emerging nanostructure (core shell, alloy, and onionlike) is determined by the chemical nature of the colliding clusters, the initial kinetic energy is an important control parameter. Structural and dynamic properties are evaluated from atom dynamics and Monte Carlo simulations.3. Bimetallic nanoclusters of core-shell (Pt–Au, Co-Ag), alloyed (Pd–Au, Cu-Au), and three-shell onionlike Cu–Ag structures were found after collision of two clusters with a given initial velocity. While the nature of the emerging nanostructure (core shell, alloy, and onionlike) is determined by the chemical nature of the colliding clusters, the initial kinetic energy is an important control parameter. Structural and dynamic properties are evaluated from atom dynamics and Monte Carlo simulations