Study of electron-molecule collision via finite-element method and r-matrix propagation technique: Exact exchange

Journal Article · Sun Oct 15 04:00:00 EDT 1995 · Journal of Computational Physics

DOI:https://doi.org/10.1016/S0021-9991(95)90153-1· OSTI ID:376977

Abdolsalami, F ^[1]; Abdolsalami, M; Perez, L; Gomez, P ^[2]

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1. Trinity Univ., San Antonio, TX (United States)
2. St. Mary`s Univ., San Antonio, TX (United States); and others

The authors have applied the finite-element method to electron-molecule collision with the exchange effect implemented rigorously. All the calculations are done in the body-frame within the fixed-nuclei approximation, where the exact treatment of exchange as a nonlocal effect results in a set of coupled integro-differential equations. The method is applied to e-H{sub 2} and e-N{sub 2} scatterings and the cross sections obtained are in very good agreement with the corresponding results the authors have generated from the linear-algebraic approach. This confirms the significant difference observed between their results generated by linear-algebraic method and the previously published e-N{sub 2} cross sections. Their studies show that the finite-element method is clearly superior to the linear-algebraic approach in both memory usage and CPU time especially for large systems such as e-N{sub 2}. The system coefficient matrix obtained from the finite-element method is often sparse and smaller in size by a factor of 12 to 16, compared to the linear-algebraic technique. Moreover, the CPU time required to obtain stable results with the finite-element method is significantly smaller than the linear-algebraic approach for one incident electron energy. The usage of computer resources in the finite-element method can even be reduced much further when (1) scattering calculations involving multiple electron energies are performed in one computer run and (2) exchange, which is a short range effect, is approximated by a sparse matrix. 17 refs., 7 figs., 5 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 376977
• Journal Information: Journal of Computational Physics, Journal Name: Journal of Computational Physics Journal Issue: 2 Vol. 121; ISSN JCTPAH; ISSN 0021-9991
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COMPUTERIZED SIMULATION
ELECTRON EXCHANGE
ELECTRON-MOLECULE COLLISIONS
FINITE ELEMENT METHOD
HYDROGEN
NITROGEN