Single electron ionization of NH$_{3}$ and CH$_{4}$ by swift proton impact

C. A. TACHINO; J. M. MONTI; O. A. FOJÓN; C. CHAMPION; R. D. RIVAROLA

Bariloche

Conferencia; XVII International Conference on the Physics of Highly Charged Ions; 2014

The influence of the description of the initial bound molecular orbitals is studied in the case of single ionization of NH$_{3}$ and CH$_{4}$ molecules by proton impact at intermediate and high collision energies. Corresponding double differential cross sections (DDCS) as a function of the energy and angle of the emitted electron, are calculated by employing two different approaches, both within the post and prior versions of the CDW-EIS (continuum distorted wave-eikonal initial state) model. In the first approximation, proposed by Senger et al. [1,2], the molecular bound wavefunction is written as a linear combination of the atomic orbitals corresponding to each atomic compound of the molecule, all of them centred on each molecular nucleus. To simplify the DDCS calculations, all the overlap terms are neglected. The coefficients of the linear combination are obtained via a population analysis. In a second approach, we use the molecular representation proposed by Roberto Moccia [3] for the ground state of XH$_{n}$-type molecules, where each molecular orbital is expressed as a linear combination of Slater-type functions all centred in the heaviest nucleus of the target. In both cases, the final states are represented by a triple product of the two projectile and target coulomb continuum factors (with different effective target charges) and a plane wave.