ELEMENTARY PROCESSES, THERMODYNAMICS AND TRANSPORT OFH2, O2 AND N2 PLASMAS

M. Capitelli

cnr imip bari italy

dept of chemistry, university of bari italy

COLLABORATORs

C.Gorse, S.Longo, P.Diomede, C.Catalfamo, G.DAmmando, M.C.Coppola

Department of Chemistry, University of Bari, Bari, Italy

D.Bruno, G.Colonna, O.De Pascale, F.Esposito, A.Laricchiuta

M.Cacciatore, M.Rutigliano

IMIP(CNR), Bari, Bari, Italy

R.Celiberto

Department of Water Engineering and Chemistry Polytechnic of Bari, Bari, Italy

a) photodissociation of H2(), D2(), HD() and H2+() b) heavy particle collision cross sections : H2(), D2() from recombinationc) H2() formation on graphited) heavy particle collision cross sections for O-O2 and N-N2 : fitting relationsd) collision integrals for O-O and O-O+ interactionse) collision integrals for N-N and N-N+ interactions: a phenomenological approach

a) thermodynamic properties of atomic hydrogen plasmab) transport properties of atomic hydrogen plasma: cut-off criteriac) negative ion source modeling

OUTLINE

Elementary Processes

Thermodynamics, Transport and Kinetics of Plasmas

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

D.R.G. Schleicher et al. Astronomy&Astrophysics 490 (2008) 521MACROSCOPIC PHOTODISSOCIATION RATE COEFFICINTS for H2() and H2+() : COMPARISON with LITERATUREH2() LYMANH2() WERNERH2+()

HEAVY PARTICLE COLLISIONSVIBRATIONALLY EXCITED MOLECULES FROM RECOMBINATION 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 barrierquasi-bound state

T = 1,000 KT = 300 KH2() FROM RECOMBINATION

O2(), N2() FROM RECOMBINATIONO2N2

ATOMIC RECOMBINATION on GRAPHITE SURFACEH2 (, 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 ISOTOPESSURFACE TEMPERATURE=500 K ENERGY = 0.07 eVM.RUTIGLIANO, M.CACCIATORE, CHEM.PHYS.CHEM. 9 (2008) 171vibrational distribution is obtained summing up population of rotational levels

HEAVY PARTICLE COLLISION CROSS SECTIONS for O-O2 and N-N2 SYSTEMSFITTING RELATIONS ACCURATE QCT CROSS SECTIONS for VIBRATIONAL DEACTIVATION VT processes DISSOCIATIONF.ESPOSITO, I.ARMENISE, G.CAPITTA, M.CAPITELLI, CHEM.PHYS 351 (2008) 91 fitting bidimensional relationsEASY INCLUSION in KINETIC MODELTEMPERATURERATE COEFFICIENT [cm3s-1]TEMPERATURERATE COEFFICIENT [cm3s-1]i=30i=40i=46i=0102030

COLLISION INTEGRALS for O-O and O-O+ INTERACTIONS involving LOW-LYING EXCITED STATESSCHEME OF CLASSICAL APPROACH

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

A PHENOMENOLOGICAL MODEL forHEAVY PARTICLE COLLISION INTEGRALSCLASSICAL COLLISION INTEGRALSINTERACTION POTENTIALPHENOMENOLOGICAL APPROACHAVERAGE INTERACTIONfitting formulas up to (4,4) orderA. LARICCHIUTA, G.COLONNA et al. Chemical Physics Letters 445 (2007) 133

PHENOMENOLOGICAL APPROACHION-NEUTRAL46NEUTRAL-NEUTRALhard interactionssoft interactions

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

INELASTIC (CHARGE TRANSFER) DIFFUSION-TYPE COLLISION INTEGRALs for N*-N+ INTERACTIONs involving HIGH-LYING EXCITED STATESDependence 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=10,000K (different electronic states of N, arising from the same electronic configuration have been considered. n=2 N(2p3 4S,2D,2P), n=3 N(2p23s 2P,4P;), n=4 N(2p24s 2P,4P;), n=5 N(2p25s 2P,4P;)

EFFECTIVE DIFFUSION-TYPE COLLISION INTEGRALSfor N-N+ INTERACTIONS involving LOW-LYING EXCITED STATESELASTIC CONTRIBUTION from PHENOMENOLOGICAL POTENTIALS andINELASTIC CONTRIBUTION from CHARGE-EXCHANGE CROSS-SECTIONST = 10,000 K

a) photodissociation of H2(), D2(), HD() and H2+() b) heavy particle collision cross sections : H2(), D2() from recombinationc) H2() formation on graphited) heavy particle collision cross sections for O-O2 and N-N2 : fitting relationsd) collision integrals for O-O and O-O+ interactionse) collision integrals for N-N and N-N+ interactions: a phenomenological approach

a) thermodynamic properties of atomic hydrogen plasmab) transport properties of atomic hydrogen plasma: cut-off criteriac) negative ion source modeling

OUTLINE

Elementary Processes

Thermodynamics, Transport and Kinetics of Plasmas

THERMODYNAMIC PROPERTIES for ATOMIC HYDROGEN PLASMAM. Capitelli, D. Giordano, G. ColonnaThe role of Debye-Hckel electronic energy levels on the thermodynamic properties of hydrogen plasmas including isentropic coefficientsPhysics of Plasmas 15(8) (2008) 082115

(curve a) energy levels from the Debye-Hckel potential [23]

(curve b) energy levels from the Coulomb potential

(curve c) only hydrogen ground state (fH= 2, cp,int(H)=0).

For curves a and b the number of levels is truncated by using the Griem cut-off, calculated self-consistently with the plasma composition.

Internal partition functionInternal specific heat

internal state contributionreaction contributionCONTRIBUTION TO SPECIFIC HEATFrozen Specific HeatReactive Specific Heat

HYDROGEN MIXTURE ISENTROPIC COEFFICIENTTotalFrozen

GROUND STATE METHODS

DEBYE HCKEL CRITERION

CONFINED ATOM APPROXIMATIONinternal energy = 0particle densityIN ANY CASE DRASTICALLY DECREASESINCREASING PRESSURE or ELECTRON DENSITY!!!TRANSPORT PROPERTIES for ATOMIC HYDROGEN PLASMA : CUT-OFF CRITERIA

EFFECT of DIFFERENT CUT-OFF CRITERIA on ATOMIC HYDROGEN NUMBER DENSITYGROUND-STATEDEBYE-HUCKELCONFINED-ATOMTrampedach et al. Astrophys. J. (2006)

DIFFUSION-TYPE COLLISION INTEGRALSVISCOSITY-TYPE COLLISION INTEGRALSCOLLISION INTEGRALs for H(n)-H+ INTERACTIONs compared withCOULOMB COLLISION INTEGRALs

case USUALEES considered as independent chemical species BUT EES collision integrals set equal to ground state ones case ABNORMALEES considered as independent chemical species withtheir own collision integrals

EFFECT of DIFFERENT CUT-OFF CRITERIA on TRANSPORT PROPERTIES of HYDROGEN PLASMAincluding ABNORMAL TRANSPORT CROSS SECTIONs for EES HEAVY PARTICLE THERMAL CONDUCTIVITYVISCOSITYD. Bruno, M. Capitelli, C. Catalfamo, A. Laricchiuta Physics of Plasmas (2008) in press

EFFECT of DIFFERENT CUT-OFF CRITERIA on TRANSPORT PROPERTIES of HYDROGEN PLASMAincluding ABNORMAL TRANSPORT CROSS SECTIONs for EES REACTIVE THERMAL CONDUCTIVITYINTERNAL THERMAL CONDUCTIVITY

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 removalRF-ICP NEGATIVE ION SOURCE

Boltzmann Tg VDFH2(v)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)EXPANSION REGION: H2() EXCITATIONH2()VIBRATIONAL DISTRIBUTION FUNCTION

0 5 10 15 20 30 (cm)(a) U. Fantz, et al., Plasma Phys. Control. Fus. 49(12B), 563-580 (2007).PGPLASMAGRIDTO THE DRIVERDRIVEREXITEXTRACTIONREGIONEXPANSION REGIONtransition from a classical sheath drop to a complete reversed sheathEXTRACTION REGION RESULTS: PG BIAS EFFECT

FUTURE PERSPECTIVEs

a) elementary gas-phase processes involving Caesium b) direct approaches for gas-phase recombinationc) H2() formation on caesiated surfacesd) approaches for collision integral calculation of highly excited states interactions

a) transport properties of air plasma with electronically excited statesb) transport of radiationc) negative ion source modeling improvements

Elementary Processes

Thermodynamics, Transport and Kinetics of Plasmas