Influence of the condensed phase state on the energy loss determination in Na-faujasite

Abstract

In porous crystals such as zeolites, there is more than one kind of cavity or channel to which small guest molecules may have access. This property may provide a variety of natural environments in which one can evaluate the dispersion energy contribution to the physical bond between different molecules. This work is aimed to determine the contribution of physical state and condensed sorbed water molecules to the stopping power measurements in zeolite material. Electronic stopping power for helium projectiles have been measured with a combined backscattering and transmission methods in different states of Y-faujasite, in the range of energy 953–2734 keV. The physical state of the zeolite has been changed by irradiating the faujasite samples with helium ions at 3 MeV up to doses 4 × 10 12–2 × 10 14 He/cm 2. The variation in the chemical structure of the Y-faujasite has been studied by means of IR absorption spectra and the Elastic Recoil Detection technique analysis (ERDA) has been used to determine the amount of hydrogen desorbed after each irradiation. The main results of these experiments are that the response to irradiation is completely different according to the irradiation fluence considered, in which case a correlation between changes in d E/d x and the nature of the modifications created by the irradiation in the material can be made.