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Introduction

Molecular structure Two-center continuum wavefunction for the ejected electron. Not oriented target nor particular rovibrational initial state in experiments Vibrational nor Rotational states resolved. Introduction. Ionization of molecules compared to atoms. Experiment. Theory.

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Introduction

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  1. Molecular structure Two-center continuum wavefunction for the ejected electron Not oriented target nor particular rovibrational initial state in experiments Vibrational nor Rotational states resolved Introduction Ionization of molecules compared to atoms Experiment Theory Omar FOJON (CONICET-UNR) Argentina

  2. Theoretical work on H2 TDCS • DWVA (Zurales et al, 1988) • DWO (Monzani et al, 1999) • Influence of vibrational states, electronic vertical transitions (Weck et al, 2000) • e+/H2+ (Fojón et al, 1996) • Effective Center Models for ion impact (Rivarola et al, 1991-2002) Omar FOJON (CONICET-UNR) Argentina

  3. Experimental work on H2 (TDCS) • Absolute Triple Differential Cross Sections (TDCS) at very high impact energy in coplanar asymmetric geometry (Chérid et al, 1989) • Relative TDCS at high impact energy (Jung et al, 1975 in coplanar asymmetric geometry Omar FOJON (CONICET-UNR) Argentina

  4. The (e,2e) process of interest is -Intermediate and high impact energies -Asymmetric coplanar geometries • Modelization • Electronic vertical transitions • Fixed molecular orientation during the collision • Neglect of exchange effects Omar FOJON (CONICET-UNR) Argentina

  5. Cross Sections • Fivefold differential cross section for coplanar asymmetric geometries • Averaging over all molecular orientations, triple differential cross sections are obtained Omar FOJON (CONICET-UNR) Argentina

  6. T-Matrix Amplitude • The prior version of the T-matrix element reads Omar FOJON (CONICET-UNR) Argentina

  7. Initial bound wavefunctions Berencz Wavefunction Heitler-London by Wang Omar FOJON (CONICET-UNR) Argentina

  8. Final wavefunction Final Bound wavefunction TEC, TCC, BBK approximations Continuum wavefunction Omar FOJON (CONICET-UNR) Argentina

  9. Two Effective Center (TEC) Model • Ionization near nucleus • Complete screening by passive electron • One continuum ks e e r1 ke e H H Omar FOJON (CONICET-UNR) Argentina

  10. TEC final wavefunction Weck, Fojón, Hanssen, Joulakian, and Rivarola, PRA 63 (2001) 042709 appears in the t-matrix element If with is chosen Omar FOJON (CONICET-UNR) Argentina

  11. Two-Center Continuum (TCC) Model Joulakian, Hanssen, Motassim and RivarolaPRA 54 (1996) 1473for H2+ • H2+ targets • Two-continuum wave function ks e e ke r1 H H Omar FOJON (CONICET-UNR) Argentina

  12. TCC wavefunction for H2 Weck, Fojón, Hanssen, Joulakian, and Rivarola, PRA 63 (2001) 042709 TCC for H2 molecules Asymptotic Charge 1 Weck, Fojón, Joulakian, Stia, Hanssen and Rivarola, PRA 66 (2002) in press Omar FOJON (CONICET-UNR) Argentina

  13. Boundary conditions satisfied Passive electron included Only one continuum: easy to handle Boundary conditions not satisfied (correction 2Zsc=1) Passive electron plays no role (correction 2Zsc=1) Two continua TEC vs. TCC TEC TCC Omar FOJON (CONICET-UNR) Argentina

  14. Omar FOJON (CONICET-UNR) Argentina

  15. Molecular BBK Model • TEC treatment • BBK correlated continuum wavefunction in the final channel ks e e ke e H H Omar FOJON (CONICET-UNR) Argentina

  16. Molecular BBK Final Continuum Wf. Omar FOJON (CONICET-UNR) Argentina

  17. Direct and Indirect terms ks e Direct Term r1p e R1 ke e H H

  18. Direct and Indirect terms ks e R2 Indirect Term e ke e r2p H H

  19. MBBK Cross Sections • Neglecting indirect terms and averaging over all molecular orientations Omar FOJON (CONICET-UNR) Argentina

  20. Conclusions and Perspectives • MBBK: Good agreement between experiments at intermediate and high impact energy • TEC and TCC: describe well experiments at high impact energy • Inclusion of e-e repulsion crucial to describe the binary and recoil peak region • Extension of TEC treatment to other diatomic molecules such as N2 Omar FOJON (CONICET-UNR) Argentina

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