Switching classical trajectory Monte Carlo method to describe two-active-electron collisions

Abstract

We propose a classical trajectory Monte Carlo method to describe two-center collisions with two active electrons. The approach is based on switching between standard four-body and three-body descriptions and it is therefore easy to implement. We demonstrate the reliability of the approach for fundamental H+H and H + +H − collisions that neither four-body nor three-body classical methods describe satisfactorily.

Interaction of Be4+ and Ground State Hydrogen Atom—Classical Treatment of the Collision

“…Up to now, the QTMC-KW [12] has been applied to a variety of problems [13]. The method and its extensions [14][15][16][17][18] use momentum-dependent effective potentials in a Hamiltonian model to stabilize realistic atomic and molecular structures, which would otherwise autoionize classically. In this work, the interaction between Be 4+ and ground state hydrogen atom is studied using the three-body CTMC and QTMC-KW in the projectile energy range between 10 and 1000 keV/au.…”

Ionization and Single and Double Electron Capture in Proton–Ar Collisions

“…The calculation at intermediate energies has been carried out by applying the s-CTMC method, which has been successfully implemented for two-electron systems in Ref. 41. We have checked that the s-CTMC yields cross sections for H formation very close to that obtained in the standard, one-electron CTMC treatment with the same model potential, but the method improves the results for H − formation, which in the standard one-electron CTMC are overestimated by almost one order of magnitude.…”

“…In order to understand the different behavior of the IEVM (34), (42), and IP2 (33), (41) formulae of H and electron production we start by considering the first term of (33):…”

“…However, when both electrons are bound to the same nucleus, a model-potential description is applied for both electrons. The method has been successfully applied H+H and H + +H − collisions, 41 2. Theoretical methods.…”

“…In this paper we carry out a theoretical study of H + + Ar collisions by applying two methods. We apply a semiclassical method with a close-coupling expansion in terms of manyelectron molecular wave functions (MFCC) with eight active electrons, and the switching classical trajectory Monte Carlo (s-CTMC) method, recently proposed by Jorge et al 41 In the classical calculations we have considered the motion of two electrons in a model potential. Both methods employ effective potentials to describe the n = 1−2 shells that do not play a significant role at energies below 500 keV, as indicated by the negligible contribution of Auger electron emission.…”