Photoinduced trapping of xenon in polymeric films at ambient temperature

A new technique which allows the storage of noble gases in polymeric films at ambient temperature was successfully developed. The trapping of the rare gases in the polymer takes place via X-ray irradiation of the gas and the polymer film by means of an X-ray tube. Concentrations up to about 2 × 1017 atoms of noble gas per cm2 of the film were obtained. The thermal energy needed for desorbing Xe from a kapton film was found to be about 16 kcal/mol which is large compared with the known values for thermal desorptions on metal surfaces. An energy shift of 1.04 ± 0.48 eV was further observed for the 5p–1s X-ray transition of trapped Xe atoms, which permits to surmise a rather strong interaction between the sorbate atoms and the sorbent molecules. Two interpretations of the observed phenomena are presented, the first involves bond ruptures and bond rearrangements in the polymer whereas the second is based on the assumption that chemisorption or persorption of Xe occurs in the polymeric substrate.