PHOTOLYSIS LASER-INDUCED FLUORESCENCE DIAGNOSTIC FOR GACL

A spatially resolved optical diagnostic for GaCl is described. The tec hnique uses 248-nm excimer laser radiation to photolyze GaCl and also to excite fluorescence in the resulting gallium atoms. This yields gal lium fluorescence at 245, 266, 287, 294, 403, and 417 nm. The method i s specific to GaCl and is not affected by the presence of a GaCl3 prec ursor. Gallium fluorescence is linear in both the GaCl partial pressur e and the laser energy under specified conditions. The photophysics of this process are contrasted to related GACl studies of dissociative e xcitation at 193 nm.