Generation of Hyperthermal Cl atoms by Laser-Induced Desorption and Photodissociation

The irradiation of metal chloride films （e. g. CsCl, AgCl and CuCl₂） on the transparent substrate by a pulsed UV（355nm）laser is used to produce intense pulses of hyperthcrmal Cl atoms. The kinetic energy distributions of of atoms are measured by a time-of-flight mass spectrometer and has a broad energy distribution in the range from 0.0leV to 5.6eV. The most probable kinetic energy of Cl atoms, which is quoted as the corresponding to the maximun of the time-of-flight trace,can be increased by increasing film thickness and laser fluence. These results might be explained by laser-induced explosive dcsorption and shock wave heatin gmechanisms.