The vibrational populations of the YO <i>A</i><sup>2</sup>Π-<i>X</i><sup>2</sup>Σ system of YO were measured in the plasmas generated after the excimer laser ablation of Y<sub>2</sub>O<sub>3</sub> in oxygen when both continuous and pulsed electric fields were applied. When an electric field is applied antiparallel to the direction of propagation of the ejected electrons, two luminous plumes appear, separated by several microseconds. The measured vibrational populations of the YO <i>A</i><sup>2</sup>Π-<i>X</i><sup>2</sup>Σ system are different for each plume. The YO <i>A</i><sup>2</sup>Π populations were nonthermal in the first plume, representing emission from chemiluminescent reactive collisions in the plume after ablation. The second emission pulse, initiated by the discharge of a high-voltage capacitor, probes the ground-state YO in the plume via electron collisions. This pulsed electric field holds promise as a diagnostic probe of the ground-state species emitted in laser ablative processes.
Daniel Fried, Toshimoto Kushida, Gene P. Reck, and Erhard W. Rothe, "YO A2Π1/2,3/2 Vibrational State Distributions Measured After the Excimer Laser Ablation of Y2O3 Using a Laser-Initiated Pulsed Discharge as a Probe," Appl. Spectrosc. 48, 248-251 (1994)