Production of fast caesium atoms in an open diffusion source by charge transfer reactions involving highly excited atoms

A component of neutral particles with hyper-thermal velocity has recently been observed in the flux from a new type of beam source for production of excited alkali atoms, the so called open diffusion source. The hyper-thermal component is probed with a time-of-flight technique and is found to consist of fast atoms with translational energies of several hundreds of electronvolts. They are formed in charge transfer reactions in the gas phase with cross sections of the order of 4000-8000 Angstrom(2), which shows that highly electronically excited atoms are involved in the reaction.