Dept. Chemistry, University of Bari, Italy
IMIP-CNR, section of Bari, Italy
We report the results obtained since the last meeting in Vien 26-28 September 2005 in the three topics covered by our group
Elementary Processes
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State-to-state radiative decay-vibrational excitation cross sections, for EV processes , proceeding through the low-lying Rydberg states (B' 1  u
+ , D 1  u
), have been calculated for H
2
and D
2
molecule. The alternative exit channel, i.e. the decay to the continuum of the ground state, resulting in the molecular dissociation ( radiative decay dissociation ), has been also considered, deriving corresponding state-resolved cross sections.
-
Resonant vibrational excitation cross sections in eV processes , proceeding through the 2  g
+ excited state of H
2
molecular ion (the so-called 14 eV resonance ), have been obtained by using the local resonance model with resolution on the final vibrational level, showing a good agreement with experiments.
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Resonant charge transfer processes has been studied in collisions involving atom-parent ion, both in electronically excited states, for nitrogen system, by using the asymptotic approach.
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Cross sections and rate coefficients for atom-molecule system, involving hydrogen isotopes, have been calculated by the quasiclassical trajectory method, with resolution on the roto-vibrational level of the molecular target and by using a new and more accurate potential energy surface. Moreover scaling relations that allow the derivation of accurate cross sections for different colliding systems from the QCT hydrogen complete database have been verified.
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Concerning nitrogen atom-molecule processes, quasiclassical calculations have been extended in translational energy up to 9 eV (previously this limit was
3eV). This allows a more reliable calculation of rate coefficients for temperature range extending to 10000K and over. For the purpose of a practical usage in kinetic codes, a complete analytical fitting of rate coefficients for both vibrational energy exchange and state specific dissociation have been performed.
-
Harpoon reactions involving caesium and hydrogen molecules in highly excited electronic states have been studied in the framework of the asymptotic approach for resonant processes.
Transport Properties of H
2
Plasmas
Transport cross sections of electronically excited states of atomic hydrogen, derived by using semiclassical approaches, have been used to calculate the transport coefficients (viscosity, thermal conductivity, electrical conductivity) of thermal plasmas in a wide range of temperatures and pressures, including the effect of external magnetic field. A tensorial reformulation of the Chapman
Eskog theory has been required and the implementation of a new numerical code. The results show the strong influence of excited states on the transport

coefficients of atomic plasmas on the parallel component of transport coefficients, not affected by magnetic field, as found in previous study, and, considering different values of the Hall parameter, allow the estimation of different effects on transverse component. Also the dependence of results on different criteria for partition function cut-off has been discussed.
Plasma kinetics
We have implemented kinetic codes to describe the kinetics of molecular plasmas (mainly hydrogen) in different non-equilibrium conditions. These codes include a) a quasi-homogeneous plasma model including a radiative-collisional model for atomic and molecular hydrogen b) a PIC-MCC (Particle In Cell with Monte-Carlo Collisions) for describing parallel plate hydrogen plasma reactors c) a 1D Euler code coupled with the kinetics of partially ionized gases to describe high enthalpy flows through nozzles of different geometries d) a DSMC (Direct Simulation with Monte Carlo collisions) model for describing shock wave propagation e) a zerodimensional code to reproduce the plasma kinetics in multipole magnetic plasmas f) a Monte Carlo code to describe the expansion zone of a negative ion source
The codes have been applied to reproduce different experimental situations. In particular effort has been devoted to the so-called caesium issue , i.e. the inclusion in the kinetic scheme of elementary processes involving caesium, in order to theoretically investigate modern negative ion surces, which include in the reactor caesium atoms, increasing significantly the H production.
References
[1] A.Laricchiuta, R.Celiberto, F.Esposito, M.Capitelli, “ State-to-state cross sections for H
2 and its isotopic variants ”, Plasma Sources Science and Technology 15 (2006)
S62-S66
[2] A.V.Kosarim, B.M.Smirnov, M.Capitelli, R.Celiberto, A.Laricchiuta, “ Resonant charge exchange involving electronically excited states of nitrogen atoms and ions ”,
Physical Review A 74 (2006) 062707
[3] M.Capitelli, I.Armenise, D.Bruno, M.Cacciatore, R.Celiberto, G.Colonna,
O.DePascale, P.Diomede, F.Esposito, C.Gorse, K.Hassouni, A.Laricchiuta, S.Longo,
D.Pietanza, M.Rutigliano “ Non-equilibrium plasma kinetics: a state-to-state approach ”, Plasma Sources Science and Technology 16 (2007) S30-S44
[4] M.Capitelli, M.Cacciatore, R.Celiberto, O.DePascale, P.Diomede, F.Esposito,
A.Gicquel, C.Gorse, K.Hassouni, A.Laricchiuta, S.Longo, D.Pagano, M.Rutigliano,
“ Vibrational kinetics, electron dynamics and elementary processes in H
2
and D
2 plasmas for negative ion production: modelling aspects ”, Nuclear Fusion 46 (2006)
S260-S274

[5] A.V.Kosarim, B.M.Smirnov, M.Capitelli, A.Laricchiuta, F.Paniccia, “ Electron impact ionization cross sections of vibrationally and electronically excited oxygen molecules ”, Chemical Physics Letters 422 (2006) 513-517
[6] F.DePalma, A.R.Casavola, M.Capitelli, “ The influence of electronic excitation on the thermodynamic properties of hydrogen plasmas ”, Journal of Thermophysics and
Heat Transfer 20 (2006) 921-925
[7] P.Diomede, S.Longo, M.Capitelli, “ Negative ion yield in low pressure radio frequency discharges in hydrogen: particle modelling and vibrational kinetics ”,
Review of Scientific Instruments 77 (2006) 03A503-5
[8] D.Pagano, C.Gorse, M.Capitelli, “ Atomic wall recombination and volume negative ion production ”, Review of Scientific Instruments 77 (2006) 03A505-7
[9] P.Diomede, S.Longo, M.Capitelli, “ Charged particle dynamics and molecular kinetics in the hydrogen post-discharge plasma ”, Physics of Plasmas 13 (2006)
113505
[10] F.Esposito, M.Capitelli, “ QCT calculations for the process N
2
(v)+N  N
2 in the whole vibrational range ”, Chemical Physics Letters 418 (2006) 581-585
(v ')+N
[11] F.Esposito, I.Armenise, M.Capitelli, “N-N
2 state to state vibrational-relaxation and dissociation rates based on quasiclassical calculations ”, Chemical Physics 331
(2006) 1-8
[12] D.Pagano, C.Gorse, M.Capitelli, “ Modelling multicusp negative ion sources ”,
(2007) submitted
[13] R.Celiberto, R.K.Janev, J.M.Wadehra, A.Laricchiuta, “ Electron-impact cross sections for 14 eV e-H
2
resonant collisions: vibrational excitation ”, (2007) submitted
[14] D.Bruno, A.Laricchiuta, M.Capitelli, C.Catalfamo, D.Giordano, “ Electronic excited states and transport properties of magnetized hydrogen plasma ” paper AIAA-
2006-3082 (37th AIAA Plasmadynamics and Lasers Conference, San Francisco,
California, 5-8 Jun 2006)
[15] D.Bruno, M.Capitelli, C.Catalfamo, A.Laricchiuta, “ Effect of electronically excited states on transport in high-temperature magnetised hydrogen plasma ”, AIP
Conference Proceedings (XXV International Symposium on Rarefied Gas Dynamics
(RGD-25), St Petersburg (Russia), 21-28 July 2006), in press
[16] M.Capitelli, R.Celiberto, F.Esposito, A.Laricchiuta, “ Cross section data for negative ion sources ”, AIP Conference Proceedings (11th Symposium on Production and Neutralization of Negative Ions and Beams (PNNIB-11) Santa Fe, New Mexico
(USA), 13-15 September (2006)), in press
[17] M.Capitelli, P.Diomede, C.Gorse, S.Longo, D.Pagano, “ State to state and charged particle kinetic modeling of time filtering and Cs addition ”, AIP Conference

Proceedings (11th Symposium on Production and Neutralization of Negative Ions and
Beams (PNNIB-11) Santa Fe, New Mexico (USA), 13-15 September (2006)), in press
[18] F.Taccogna. M.Capitelli, S.Longo and R.Schneider “ Modeling of a Negative
Ion Source I. Gas Kinetics and Dynamics in the Expansion Region"
Phys.Plasmas (2007) in press
[19] D.Bruno, A.Laricchiuta, M.Capitelli and C.Catalf
amo” Effect of Electronic
States on transport in magnetized Hydrogen Plasmas” Phys. Plasmas
14,022303(2007)
[20] D.Bruno, A.Laricchiuta, M.Capitelli and C.Catalfamo” Transport of electrionic energy in thermal plasmas” Phys. Plasmas (2007) in press