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A.Laricchiuta

A.Laricchiuta. IMIP-CNR, sezione di Bari, Italy. !!!non-equilibrium conditions!!!. STATE-to-STATE KINETIC APPROACH. ELEMENTARY PROCESSES. database of state-resolved cross sections. molecular dynamic calculations. molecular beam experiments. MODELING of PLASMA SYSTEMS

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A.Laricchiuta

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  1. A.Laricchiuta IMIP-CNR, sezione di Bari, Italy

  2. !!!non-equilibrium conditions!!! STATE-to-STATE KINETIC APPROACH ELEMENTARY PROCESSES database of state-resolved cross sections molecular dynamic calculations molecular beam experiments MODELING of PLASMA SYSTEMS for AEROSPACE APPLICATIONS (shuttle re-entry simulation)

  3. ELECTRON IMPACT induced PROCESSES in HOMONUCLEAR DIATOMIC MOLECULES RESONANT VIBRATIONAL EXCITATION ofN2 NON-DISSOCIATIVE IONIZATION of N2 VIBRONIC EXCITATION and (PRE)DISSOCIATION of O2 andN2

  4. IONIZATION N2-N2+ system POTENTIAL ENERGY CURVES F.R. Gilmore, J.Q.R.S.T. 5, 369 (1965)

  5. SIMPLIFIED APPROACH ELECTRON-IMPACT IONIZATION: THEORETICAL APPROACH IONIZATION CROSS SECTION of atoms by electron impact CLASSICAL METHODS (THOMSON) ƒ universal function IONIZATION CROSS SECTION of vibrationally excited molecules by electron impact Franck-Condon factor ionization potential

  6. we find the universal function f(x) on the basis of the experimental data NITROGEN

  7. ELECTRON-IMPACT IONIZATION from GROUND STATE cross section [10-17 cm2]

  8. CROSS SECTION DEPENDENCE on the INITIAL VIBRATIONAL QUANTUM NUMBER

  9. ionic state Van Zyl this work 0.320 0.30 0.535 0.50 0.145 0.20 ELECTRON-IMPACT IONIZATION from GROUND STATE cross section [10-17 cm2] E=100eV [J.Geophys.Res. 100, 23755 (1995)]

  10. ELECTRON-IMPACT IONIZATION from EXCITED STATE

  11. VIBRONIC EXCITATION PREDISSOCIATION DIRECT DISSOCIATION EXCITATION-DISSOCIATION

  12. M + M DIRECT DISSOCIATION M2* VIBRONIC EXCITATION M + M PREDISSOCIATION A* e A* n’ curves crossing X M2

  13. intermediate energy region??? Impact Parameter Method quantistic effects (resonances) suitable for approximations (Born and Born-Bethe Approximations) accurate quantum treatments (R-Matrix, Close-Coupling …) • cross section vibrational-dependence • reasonable ACCURACY (agreement with experimental data) • low computational cost BUT • no treatment of resonance effects • suitable only for allowed transitions threshold region high energy region

  14. Electron Impact Excitation/Dissociation Theoretical Approach: IMPACT PARAMETER METHOD • SEMICLASSICAl Method (quantal target - classical electron projectile) • ALLOWED Transitions • Degenerate Rotational Levels A.U. Hazi, Phys.Rev. A 5, 23 (1981) M.J. Redmon, B.C. Garrett, L.T. Redmon, C.W. McCurdy, Phys.Rev.A 32, R. Celiberto, T.N. Rescigno, Phys.Rev. A 47, 1939 (1993)

  15. CODE SCHEME GAMESS (General Atomic and Molecular Electronic Structure System ) GOS FAUST BORN Cross Section Potential Energy Curves Transition Dipole Moment Impact Parameter IMPACT Cross Section

  16. O2 system POTENTIAL ENERGY CURVES: Schumann-Runge transition

  17. E=30eV E=30eV DISSOCIATIVE O2 CHANNELS

  18. CROSS SECTION DEPENDENCE on the INITIAL VIBRATIONAL QUANTUM NUMBER E=30eV

  19. O2 THEORETICAL GLOBAL DISSOCIATIVE RATE COEFFICIENTS

  20. STATE-TO-STATE CROSS SECTIONS E=30eV nf = 4 nf = 7 nf = 11

  21. COMPARISON with EXPERIMENTS ni = 0

  22. N2 W.C. Ermler, J. Phys. Chem. 86, 1305 (1982)

  23. n=0 P.C. Cosby, J. Chem. Phys. 98, 9544 (1993) theoretical global predissociative cross sections

  24. theoretical global predissociative rate coefficients

  25. Direct Dissociation through the excited state Vibronic Excitation Dissociation through Predissociative Channels The N2 Birge-Hopfield system D.Spelsberg, W.Meyer, Journal of Chemical Physics 115 (2001) 6438

  26. E=40eV E=40eV X 1Sg (ni)  b 1Pu X 1Sg (ni)  b 1Pu (continuum)

  27. CROSS SECTION DEPENDENCE on the INITIAL VIBRATIONAL QUANTUM NUMBER

  28. E.C. Zipf, M.R. Gorman, Journal of Chemical Physics 73 (1980) 813

  29. STATE-TO-STATE CROSS SECTIONS

  30. COMPARISON of electron-molecule and atom-molecule collision RATE COEFFICIENTS N2 (n,j=0) O2 (n,j=0)

  31. resonant electron capture electron detachment RESONANT VIBRATIONAL EXCITATION

  32. resonant vibrational excitation cross section (Schwinger multichannel method) N2 resonant vibrational excitation rate coefficients J=50 W.M. Huo, V.McKoy, M.A.P.Lima T.L.Gibson , in "Thermophysical aspects of reentry flows", J.N.Moss and C.D. Scott eds., AIAA, New York (1986).

  33. M.Capitelli Department of Chemistry, University of Bari, Italy IMIP-CNR, sezione di Bari, Italy R.Celiberto DICA, Politecnico di Bari, Italy B.M.Smirnov, A.V.Kosarim Institute for High Temperatures of RAS, Moscow, Russia

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