Fragmentation of methane molecules by proton and antiproton impact*
Department of Physics and Astronomy, York University, Toronto, Ontario, M3J 1P3, Canada
Received: 15 November 2016
Received in final form: 19 January 2017
Published online: 21 March 2017
Proton and antiproton collisions with methane molecules have been investigated in the impact energy range of 20–5000 keV. To address the multi-centre nature of the system, a spectral representation of the molecular Hamiltonian is used in conjunction with the independent electron model. The initially populated molecular orbitals are expanded in terms of a single-centred basis and the two-centre basis generator method is employed to solve the time-dependent single-electron Schrödinger equations. The single-electron solutions are complemented with a dynamical decay-route fragmentation model based on fixed branching ratios from [H. Luna, E.G. Cavalcanti, J. Nickles, G.M. Sigaud, E.C. Montenegro, J. Phys. B 36, 4717 (2003)] to obtain the cross sections for the production of CH4+, CH3+, CH2+, CH+ and C+ fragments. In the case of proton impact the calculations underestimate the measurements for CH4+ and CH3+, while good agreement is observed for the other fragments. A better consistency is found for antiprotons, particularly, for the production of CH4+, CH2+ and CH+.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2017