Formation and measurement of cluster beams at gasdynamic cooling of CF2HCl molecules

The clustering of CF2HCl (Freon-22 refrigerant) molecules is found to take place when these molecules are dynamically cooled in a pulsed supersonic beam. A method of CF2HCl cluster beam diagnostics is developed that combines UV multiphoton ionization, time-of-flight mass spectroscopy, and cluster IR photodissociation. The velocity of directed motion of (CH2HCl)n clusters, as well as the longitudinal and transverse velocities of their thermal motion, are measured at different stagnation pressures P0. The cluster mean size and the degree of clustering in the flow are estimated depending on supersonic flow conditions.