Laser-induced fluorescence studies of excimer laser ablation of Al ₂O₃

We have used laser-induced fluorescence to measure the energy distributions of Al atoms and AlO molecules produced by excimer laser ablation of Al 2O3. Excimer laser fluences close to the threshold for ablation were used to minimize the effects of gas phase collisions. The kinetic energies of both species were high, ∼4 eV for Al and ∼1 eV for AlO, but the AlO rotational and vibrational energies were quite low, corresponding to a temperature of ∼600 K. These results rule out thermal vaporization and provide indirect support for an electronic ablation mechanism.