A number of factors have been identified as affecting the gas phase oxidation of cations during pulsed laser ablation of lead zirconate titanate (PZT), by using energy dispersive mass spectrometry (EDMS). These phenomena are known to be critical to the deposition of high quality thin films of PZT. However, to isolate the role of each cation species and the influence of its gas phase properties, we have also looked beyond the ablation of the PZT ceramic. In this paper, we detail our observations during pulsed laser ablation of electroceramic and metallic targets, specifically PZT, Pb and Ti. We have observed the evolution and transport of molecular species during gas phase expansion over a wide range of oxygen pressures (10−7 - 10−1 mbar) and laser fluences (0.3 -10 Jcm−2). The yields of the molecular ion species are strongly dependent upon the number density of the background gas. We propose an interpretation of the relative yields of the species based upon their respective gas phase binding energies and their ease of formation based upon the reaction thermodynamics and reaction cross-section of each species.