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 P ₀. The cluster mean size and the degree of clustering in the flow are estimated depending on supersonic flow conditions.