The influence of the Coulomb explosion on the energy loss of H2+ and H3+ molecules channeling along the Si 〈1 0 0 〉 direction

In this work we have measured the contribution of the Coulomb explosion to the electronic stopping power of molecular hydrogen ions (H2+ and H3+) channeling along the Si 〈1 0 0〉 direction. We have used a SIMOX target, consisting of crystalline Si 〈1 0 0〉 with a buried layer of SiO2. The measurements of the energy loss of H+, H2+ and H3+ have been carried out using the standard channeling Rutherford backscattering spectrometry. The energy loss has been measured around the Si 〈1 0 0〉 channel at a fixed energy per nucleon (150 keV/amu) as a function of the tilt and azimuthal angles. The present results show the effect of Coulomb explosion, which enlarges the protons traversal energy and consequently the channeling energy loss. This heating effect due to H3+ ions is about two times larger than H2+ molecules and amounts to about 5% of the total stopping power.