We present in this paper a study of the radiation emitted after the explosion of clusters of propane and carbon dioxide. The highly charged ions produced in the explosion can resonantly transfer an electron from the buffer gas, helium, into highly excited states. Radiation of wavelength as short as 11.6 nm was measured from O5+, and shorter than 4 nm from C4+.

Phys. Rev. A

Toma, E. S., & Muller, H. G. (2002). X-ray emission after laser disintegration of clusters of carbon-containing molecules. Phys. Rev. A, 66(Article number: 13205), 1–7.