E LEMENTARY P ROCESSES , T HERMODYNAMICS AND T RANSPORT OF H 2 , O 2 AND N 2 P LASMAS

1. ELEMENTARY PROCESSES, THERMODYNAMICSAND TRANSPORTOF H2, O2AND N2 PLASMAS

2. COLLABORATORs

3. OUTLINE • a) photodissociation of H2(), D2(), HD() and H2+() • b) heavy particle collision cross sections : H2(), D2() from recombination • c) H2() formation on graphite • d) heavy particle collision cross sections for O-O2 and N-N2 : fitting relations • d) collision integrals for O-O and O-O+ interactions • e) collision integrals for N-N and N-N+ interactions: a phenomenological approach • a) thermodynamic properties of atomic hydrogen plasma • b) transport properties of atomic hydrogen plasma: cut-off criteria • c) negative ion source modeling

4. PHOTODISSOCIATION PROCESSES for H2(), D2(), HD() and H2+() • LYMAN and WERNER SYSTEMS • HIGH-ENERGY EXTRAPOLATION for STATE-DEPENDENT CROSS SECTIONS • derivation of • STATE-DEPENDENT PHOTODISSOCIATION RATE COEFFICIENTS • MACROSCOPIC PHOTODISSOCIATION RATE COEFFICIENT (ktot) • FITTING FORMULAS

5. MACROSCOPIC PHOTODISSOCIATION RATE COEFFICINTS for H2() and H2+() : COMPARISON with LITERATURE H2() WERNER H2() LYMAN H2+() D.R.G. Schleicher et al. Astronomy&Astrophysics 490 (2008) 521

6. HEAVY PARTICLE COLLISIONS VIBRATIONALLY EXCITED MOLECULES FROMRECOMBINATION • QCT SIMULATION • RECOMBINATION RATE COEFFICIENTs • from QCT DISSOCIATION by DETAILED BALANCE • THREE-BODY RECOMBINATION • from RBC (Roberts, Bernstein & Curtiss) THEORY • TWO-STEP BINARY COLLISION rotational barrier quasi-bound state

7. H2() FROMRECOMBINATION T = 1,000 K T = 300 K

8. O2(), N2() FROMRECOMBINATION O2 N2

9. ATOMIC RECOMBINATION on GRAPHITE SURFACE H2 (, j) NASCENT DISTRIBUTIONs • SEMI-CLASSICAL MODEL • ELEY-RIDEAL MECHANISM (H CHEMISORBED at the SURFACE with a chemisorption well of 0.52eV ) • PROBABILITIES dependence on • SURFACE TEMPERATURE • IMPACT ENERGY • ISOTOPES vibrational distribution is obtained summing up population of rotational levels SURFACE TEMPERATURE=500 K ENERGY= 0.07 eV M.RUTIGLIANO, M.CACCIATORE, CHEM.PHYS.CHEM. 9 (2008) 171

10. HEAVY PARTICLE COLLISION CROSS SECTIONS for O-O2 and N-N2 SYSTEMS FITTING RELATIONS • ACCURATE QCT CROSS SECTIONS for • VIBRATIONAL DEACTIVATION VT processes • DISSOCIATION fitting bidimensional relations EASY INCLUSION in KINETIC MODEL 30 i=30 20 10 i=40 RATE COEFFICIENT [cm3s-1] RATE COEFFICIENT [cm3s-1] i=0 i=46 TEMPERATURE TEMPERATURE F.ESPOSITO, I.ARMENISE, G.CAPITTA, M.CAPITELLI, CHEM.PHYS 351 (2008) 91

11. COLLISION INTEGRALS for O-O and O-O+ INTERACTIONS involving LOW-LYING EXCITED STATES SCHEME OF CLASSICAL APPROACH

12. EFFECTIVE DIFFUSION-TYPE COLLISION INTEGRALS for O-O+ INTERACTIONS involving LOW-LYING EXCITED STATES ELASTIC CONTRIBUTION from POTENTIALS and INELASTIC CONTRIBUTION from CHARGE-EXCHANGE CROSS-SECTIONS A.LARICCHIUTA, D.BRUNO, M.CAPITELLI, R.CELIBERTO, C.GORSE, G.PINTUS, CHEM.PHYS.LETT. 344 (2008) 13

13. “tuplet” () characterising the colliding system A PHENOMENOLOGICAL MODEL for HEAVY PARTICLE COLLISION INTEGRALS PHENOMENOLOGICAL APPROACH AVERAGE INTERACTION INTERACTION POTENTIAL CLASSICAL COLLISION INTEGRALS fitting formulas up to (4,4) order A. LARICCHIUTA, G.COLONNA et al. Chemical Physics Letters 445 (2007) 133

14. INTERACTION POTENTIAL FEATURES correlation formulas from physical properties of colliding partners POLARIZABILITY, CHARGE and NUMBER of ELECTRONS EFFECTIVE in POLARIZATION F.PIRANI et al. International Review in Physical Chemistry 25 (2006) 165 PREDICTION of POTENTIAL PARAMETER for UNKNOWN SYSTEMS PHENOMENOLOGICAL APPROACH 4 ION-NEUTRAL 6 NEUTRAL-NEUTRAL soft interactions hard interactions

15. COLLISION INTEGRALS COMPARISON between CLASSICAL and PHENOMENOLOGICAL APPROACHES phenomenological approach LARICCHIUTA et al. (2008) CAPITELLI et al. (1972)

16. INELASTIC (CHARGE TRANSFER) DIFFUSION-TYPE COLLISION INTEGRALs for N*-N+ INTERACTIONs involving HIGH-LYING EXCITED STATES Dependence of diffusion-type collision integrals for the interaction N+(3P)-N on the principal quantum number of the atom valence shell electrons, n, at T=10,000 K (different electronic states of N, arising from the same electronic configuration have been considered. n=2 N(2p34S,2D,2P), n=3 N(2p23s 2P,4P;), n=4 N(2p24s 2P,4P;), n=5 N(2p25s 2P,4P;)

17. EFFECTIVE DIFFUSION-TYPE COLLISION INTEGRALS for N-N+ INTERACTIONS involving LOW-LYING EXCITED STATES ELASTIC CONTRIBUTION from PHENOMENOLOGICAL POTENTIALS and INELASTIC CONTRIBUTION from CHARGE-EXCHANGE CROSS-SECTIONS T = 10,000 K

18. OUTLINE • a) photodissociation of H2(), D2(), HD() and H2+() • b) heavy particle collision cross sections : H2(), D2() from recombination • c) H2() formation on graphite • d) heavy particle collision cross sections for O-O2 and N-N2 : fitting relations • d) collision integrals for O-O and O-O+ interactions • e) collision integrals for N-N and N-N+ interactions: a phenomenological approach • a) thermodynamic properties of atomic hydrogen plasma • b) transport properties of atomic hydrogen plasma: cut-off criteria • c) negative ion source modeling

19. THERMODYNAMIC PROPERTIES for ATOMIC HYDROGEN PLASMA M. Capitelli, D. Giordano, G. Colonna The role of Debye-Hückel electronic energy levels on the thermodynamic properties of hydrogen plasmas including isentropic coefficients Physics of Plasmas 15(8) (2008) 082115

20. Internal partition function Internal specific heat

21. CONTRIBUTION TO SPECIFIC HEAT Reactive Specific Heat Frozen Specific Heat internal state contribution reaction contribution

22. HYDROGEN MIXTURE ISENTROPIC COEFFICIENT Frozen Total

23. TRANSPORT PROPERTIES for ATOMIC HYDROGEN PLASMA : CUT-OFF CRITERIA • GROUND STATE METHODS • DEBYE HÜCKEL CRITERION • CONFINED ATOM APPROXIMATION internal energy = 0 IN ANY CASE DRASTICALLY DECREASES INCREASING PRESSURE or ELECTRON DENSITY!!! particle density

24. EFFECT of DIFFERENT CUT-OFF CRITERIA on ATOMIC HYDROGEN NUMBER DENSITY GROUND-STATE DEBYE-HUCKEL CONFINED-ATOM Trampedach et al. Astrophys. J. (2006)

25. COLLISION INTEGRALs for H(n)-H+ INTERACTIONs compared with COULOMB COLLISION INTEGRALs VISCOSITY-TYPE COLLISION INTEGRALS DIFFUSION-TYPE COLLISION INTEGRALS

26. case USUAL EES considered as independent chemical species BUT • EES collision integrals set equal to ground state ones • case ABNORMAL EES considered as independent chemical species with • their own collision integrals

27. GROUND-STATE DEBYE-HUCKEL CONFINED-ATOM EFFECT of DIFFERENT CUT-OFF CRITERIA on TRANSPORT PROPERTIES of HYDROGEN PLASMA including ABNORMAL TRANSPORT CROSS SECTIONs for EES HEAVY PARTICLE THERMAL CONDUCTIVITY VISCOSITY D. Bruno, M. Capitelli, C. Catalfamo, A. Laricchiuta Physics of Plasmas (2008) in press

28. GROUND-STATE DEBYE-HUCKEL CONFINED-ATOM EFFECT of DIFFERENT CUT-OFF CRITERIA on TRANSPORT PROPERTIES of HYDROGEN PLASMA including ABNORMAL TRANSPORT CROSS SECTIONs for EES REACTIVE THERMAL CONDUCTIVITY INTERNAL THERMAL CONDUCTIVITY

29. RF-ICP NEGATIVE ION SOURCE • 3 CRITICAL AREAS (“remote” source) • Source chamber (driver): • ICP (transformer) heating at high RF power • No sheath losses • Hot electrons • Expansion region: • H2 vibrational excitation • Extraction region: • Magnetic filtering • Cold electrons • H- production (surface/volume) • Electron removal

30. EXPANSION REGION: H2() EXCITATION Boltzmann Tg VDF H2(v) vibrational distribution function H2() VIBRATIONAL DISTRIBUTION FUNCTION (*) J. R. Hiskes et al.,J. Appl. Phys.53(5), 3469 (1982) (**) O. Fukumasa, K. Mutou, H. Naitou, Rev. Sci. Instrum. 63(4), 2693 (1992)

31. FUTURE PERSPECTIVEs • a) elementary gas-phase processes involving Caesium • b) direct approaches for gas-phase recombination • c) H2() formation on caesiated surfaces • d) approaches for collision integral calculation • of highly excited states interactions • a) transport properties of air plasma with electronically excited states • b) transport of radiation • c) negative ion source modeling improvements