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

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

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

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

5. 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
SIMPLIFIED APPROACH
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. ELECTRON-IMPACT IONIZATION from GROUND STATE
cross section [10-17 cm2]
ionic state Van Zyl this work
E=100eV
[J.Geophys.Res. 100, (1995)]

10. ELECTRON-IMPACT IONIZATION from EXCITED STATE

11. EXCITATION-DISSOCIATION
VIBRONIC EXCITATION
PREDISSOCIATION
DIRECT DISSOCIATION

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

13. intermediate energy region??? Impact Parameter Method
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
quantistic effects
(resonances)
suitable for approximations
(Born and Born-Bethe Approximations)
accurate quantum treatments
(R-Matrix, Close-Coupling …)

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. DISSOCIATIVE O2 CHANNELS
E=30eV

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

24. predissociative rate coefficients
theoretical global
predissociative rate coefficients

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

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

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 VIBRATIONAL EXCITATION
resonant electron capture
electron detachment

32. N2 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 R.Celiberto B.M.Smirnov, A.V.Kosarim
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