Oxygen K-shell photoabsorption spectra of photoionized CO2plasmas

We report oxygen K-shell photoabsorption measurements in CO2 plasmas, using a table-top laser produced plasma soft X-ray and extreme ultraviolet (EUV) source. Significant differences are observed between the photoabsorption spectra of the neutral CO2 molecule and photoionized CO2 plasmas, as new spectral features emerge in the case of the latter. These features are attributed to 1s → 2p photoexcitation in O, O+ , O 2+ species identified with the aid of calculations performed with the Cowan suite of atomic structure codes. Such signatures of atomic ions in the photoionized plasma point to the fragmentation of the parent molecule upon absorption of a soft X-ray photon.