Role of electron saddle swaps in the photon spectra following Li3+charge-exchange collisions with H*(n= 2), Na(3

S. Otranto

¹

,

Ronnie Hoekstra

²

,

R. E. Olson

³

Abstract

The role of electron saddle swaps in collisions of bare Li with metastable hydrogen and alkali-metal atoms is investigated by means of the classical trajectory Monte Carlo method. In particular, we show that oscillations as a function of collision energy in the photon spectra resulting from charge exchange are directly related to the number of potential-saddle crossings that a receding electron can achieve during a given reaction. The range of impact energies spanned is 0.01-50 keV/amu, an area of interest for diagnostic purposes in tokamak nuclear fusion power reactors.

Extension of CTMC Calculations to Multielectron Systems

“…Figures 5. 13 For more details, see [10] curves) were compared with available experiments (symbols) and previous quantum calculations.…”

“…Very recently, Li 3+ + Li (2s, 2p o and 2p 1 ) were studied in details theoretically in the energy range 0.1-100 keV/amu [12]. However, since no experimental data is available for this system, quantum calculations were compared with CTMC calculations performed earlier [13]. Figure 5.17 shows the results of quantum (dashed blue curves) and classical (full red curves) partial SC cross sections as a function of E p for n varying from 3 to 7.…”

“…Fig.5 13. Total SC cross sections following He 2+ + Na (3s) collisions as a function of the projectile energyE p .…”

Electron capture in collisions of Li3+ ions with ground and excited states of Li atoms*

“…The total electron capture cross section was given for the energy range 0.5-5 keV/u. The classical trajectory Monte Carlo (CTMC) method was also employed to calculate the total and n-partial charge transfer cross sections by Otranto et al [10] in the energy region 0.01-100 keV/u. However, the nl-state selective charge transfer cross sections for the Li 3+ -Li(1s 2 2s) system and the collisions involving excited Li atoms were not reported until now.…”

Classical and semiclassical non-perturbative treatments of the electron transfer process in the collisional system proton-hydrogen involving initial excited states

“…In addition, the CTMC method is a good approximation at intermediate velocities to investigate electron transfer and ionization processes induced by impact of bare ions [28]. Note that CTMC has been recently used even for collisions between ions and complex targets, e.g., N a(3s), N a * (3p), Li(2s), Ar and He, where the active electron is subject to non-coulomb interactions and requires the use of model potentials [29,30] Nowadays the impressive progress of highlyparallel computers allows the use of the SC-AOCC approach with very large basis sets, which were unusable before due to prohibiting CPU execution time. Therefore, our purpose in this paper is to present a study of the capture processes for proton-hydrogen collisions involving initial excited states, up to H(n ), using non-perturbative SC-AOCC and, for comparison, CTMC approaches.…”