Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)
A 12.44: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
Nonlocal effects in the electron energy spectra for associative detachment in collisions of F−, Cl− and Br− with hydrogen atoms⋆ — •F.A.U. Thiel2, M. Cízek1, J. Horácek1, and H. Hotop2 — 1Department of Theoretical Physics, Charles University Prague, 180 00 Praha 8, Czech Republic — 2Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany
Using an improved nonlocal resonance theory, total cross sections,
rovibrational final state
distributions and electron spectra for low-energy (< 2 eV) associative
detachment (AD) collisions
between hydrogen atoms and halogen anions X− (X= F, Cl, Br) as well as
deuterium atoms and F− ions have been calculated. The model involves
realistic long-range
interactions for the H + X− systems and takes into account the
dependence of the
dipole-modified threshold exponent on internuclear distance. Good
agreement is found between
experimental data for the total AD cross sections and the theoretical
results. In the calculated
electron energy spectra nonlocal effects are manifest through a step
structure which is (almost)
independent of collision energy; this structure should therefore be
observable in experiments
with rather modest collision energy resolution. Electron spectra are
presented
which correspond to realistic experimental conditions with regard to the
energy widths of the
electron spectrometer and the collision energy distribution. The
final state distributions in the formed HX(v,J) molecules are reported
for a thermal kinetic energy
distribution at T≈ 300 K; for HF, DF, and HCl the rotational-summed
vibrational populations
pv are compared with previous results.
⋆ This work has been supported by the Deutsche
Forschungsgemeinschaft.