DETECTION OF ALO MOLECULES PRODUCED BY KRF LASER-ABLATED AL ATOMS IN OXYGEN GAS AND PLASMA ENVIRONMENTS

Experiments have been performed to measure, in real time, the formatio n of AlO molecules from laser-ablated Al atoms in oxygen gas and plasm a environments. The Al atom plume is generated by focusing a KrF laser (4 J/cm(2)) on Al metal targets or polycrystalline Al2O3 (alumina) ce ramic. AlO molecule formation has been characterized by emission spect roscopy at 464.82 and 484.22 nm molecular bandheads. Time-integrated a nd time-resolved optical emissions have been measured of laser-ablated Al atoms interacting with oxygen or argon neutral-gas versus plasma b ackgrounds generated by a high-voltage capacitive discharge. Results i ndicate that gas/plasma-phase reactions occur between laser-ablated Al atoms and oxygen. Optimal enhancement of AlO optical emission is meas ured in oxygen plasmas at about 200 mTorr fill pressure. (C) 1995 Amer ican Institute of Physics.