FULLY DIFFERENTIAL CROSS SECTIONS IN COLLISIONS OF TOTALY STRIPPED IONS WITH CH4 MOLECULE AT INTERMEDIATE ENERGIES

L. F. MENCHERO; S. OTRANTO

Conferencia; 10th European Conference on Atoms Molecules and Photons ECAMP X; 2010

We show theoretical calculations of Fully Differential Cross Sections (FDCS) of thesingle ionization of CH4 molecule by H+, He2+ and C6+ impact in the MeV/amu energyrange.During the last decade, the development of the Cold Target Recoil Ion MomentumSpectroscopy (COLTRIMS) [1,2] made possible the measurement of single ionizationFDCS for ion—atom and ion—molecule collisions. The good understanding of chargedparticles collision processes with organic molecules is valuable in fields other thanatomic physics, like in medicine, due to its implications on therapy and tumourtreatment.In this work, we apply a Born-CDW method which was successfully applied to ion—atom collisions [3], and that we have generalized for ion—molecule collisions. Theinitial electron wavefunctions for the different molecular orbitals are taken from Moccia[4]. These orbitals are also used to determine the electronic potential seen by theelectron once emitted to the continuum. These potentials resemble asymptotically deCoulomb potential -1/r but tend to the -6/r behaviour in the vicinity of the nucleus of theC atom. The presence of the H atoms, provides an anisotropy which is smoothed out byperforming an angular integration of the potential.In the figure we show the ionization FDCS for 2 MeV/amu H+ + CH4 collisions as afunction of the emitted electron angle in the collision plane. The configuration shown inthe figure corresponds to an emitted electron energy of 5 eV for three different values ofthe projectile momentum transfer.