CHROMIUM CLUSTER FORMATION UNDER RESONANT AND NONRESONANT LASER-ABLATION

Laser ablation pulses have been used to effect the multiphoton ionizat ion of a Cr2O3 target. Cluster ions of type Cr2Oy+ have been detected from the Cr2O3 target by multiphoton laser ablation ionization in the visible range. Cr-2(+) and Cr2O+ were also observed. Results from visi ble and ultraviolet wavelengths are compared and interpreted with refe rence to the known electronic states of CrO and CrO+. The results obta ined from an emission-time resolved spectroscopy study of the Cr2O3 ta rget confirm the presence of the neutral species CrO in the laser-indu ced plasma plume. When resonant laser ablation ionization is used to f orm the excited state of the chromium ion (D-4(4)) at 295.6 nm cluster s ions are observed. In contrast to this, these types of clusters are not formed in the non-resonant laser ablation ionization of the Cr2O3 target.