Chromium cluster formation under resonant and non-resonant laser ablation

Laser ablation pulses have been used to effect the multiphoton ionization of a Cr2O3 target. Cluster ions of type CrxOy+ 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 visible and ultraviolet wavelengths are compared and interpreted with reference to the known electronic states of CrO and CrO+. The results obtained from an emission-time resolved spectroscopy study of the Cr2O3 target confirm the presence of the neutral species CrO in the laser-induced plasma plume. When resonant laser ablation ionization is used to form the excited state of the chromium ion (4D4) at 295.6 nm clusters 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.