Laser-driven flow reactor as a cluster beam source

Abstract

A novel technique for the production of expansion-cooled cluster beams from materials with low vapor pressure is presented. The clusters are produced in a flow reactor from gas phase reactants by aggregation of CO2-laser-induced decomposition products. By introducing a conical nozzle into the reaction zone, they are extracted into a molecular beam apparatus and analyzed with a time-of-flight mass spectrometer. Depending on the type of CO2-laser employed, the source can be operated in the pulsed or continuous mode. The generation of carbon and silicon clusters is demonstrated by decomposing gaseous C2H2 and SiH4, respectively. The laser-driven cluster course is also employed to generate fullerenes and nanosized silicon particles.