Diagnostics and modeling of RF discharge dissociation in N/sub 2/O

Kline, L. E.; Partlow, W. D.; Young, Robert M.; Mitchell, Robert

doi:10.1109/27.106825

Cited by 46 publications

(73 citation statements)

References 18 publications

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“…30 In this respect, most three body reactions can be disregarded at low pressures without noticeable changes in the predicted results. 31 Similarly, ions are usually neglected too in the chemistry of neutrals for pressures higher than 0.1-1 mbar, 32 due to very low ionisation rates (< 10 -4 ) in this kind of plasmas. In any case, a careful diagnostics of cold plasmas of these species at different pressures would be very convenient in order to identify and characterize the processes playing the key role for each pressure region.…”

Section: Introductionmentioning

confidence: 99%

Low-Pressure DC Air Plasmas. Investigation of Neutral and Ion Chemistry

et al. 2005

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The neutral and charged species present in a direct current (dc) hollow cathode, gas flow, air reactor are experimentally studied by quadrupole mass spectrometry. The degree of ionization of the plasma and the electron mean temperature with decreasing air pressure, for constant discharge current, are measured with a double Langmuir probe. The chemical composition of the plasma changes appreciably over the 3 x 10(-3) to 5 x 10(-2) mbar range investigated: at the lowest pressures studied, O2 dissociation is up to 60% and the concentration of NO is half that of N2; concerning ions, NO+ and N2+ are dominant for the whole pressure range. A kinetic model of the plasma including electrons, neutrals, and positive ions is developed to account for the experimental observations; it is consistent with energy balance and predicts that heterogeneous processes are the main source of NO and that the contribution of ions to the global chemistry of neutrals is of minor significance even for the lowest pressures.

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Section: Introductionmentioning

confidence: 99%

Low-Pressure DC Air Plasmas. Investigation of Neutral and Ion Chemistry

et al. 2005

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“…By contrast, in plasma chemistry there is no accepted standard measure, although in previous work we have adopted the G value.17J8 This practice was originated by Burton2 and finds support in the work of both Eremin, who correlated the yield of products with the volume energy density in the plasma,19 and Kline, who has linked yields to the energy absorbed per molecule of reactant. 20 We report herein experimental measurements of the yield of destroyed ammonia, G(-NH3), obtaing using a low pressure, inductively coupled radio frequency discharge. We make a quantitative comparison of our values of G(-NH3) with those tabulated by Peterson9 for ionizing radiation and also with those which we have calculated previous1yl7 using experimental results21 obtained with a capacitatively coupled radio frequency discharge.…”

Section: Introductionmentioning

confidence: 99%

Radio frequency plasma decomposition of ammonia: a comparison with radiation chemistry using the G value

Miller¹,

Baird²

1993

J. Phys. Chem.

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We have measured G(-NH3) for ammonia vapor passing through a 13.56 MHz, inductively coupled discharge operating within a wide range of pressures (3.5-40 Torr), flow rates (1-3 L/min (STP)), and absorbed power (0.2-1.4 kW). Under these conditions, we found values of G(-NH3) lying between 4.2 and 30 molecules/ 100 eV. By comparison, under similar conditions, the efficiency of ammonia conversion by a radio frequency, capacitatively coupled discharge is 6.0-20 molecules/lOO eV (Baird, J. K.; Miller, G. P.; Li, N. J. Appl. Phys. 1990, 68, 3361), while for ionizing radiation it is 2.7-10 molecules/lOO eV (Peterson, D. B. The Radiation Chemistry of Gaseous Ammoniu, Report No. NSRDS-NBS 44, U S . Department of Commerce, Washington, DC, 1974). The differences are probably due to the specific form assumed by the electron velocity distribution in each case. The similarities with respect to order of magnitude, however, may have their origin in a common reaction mechanism. Exploiting this hypothesis, we have derived a formula for G(-NH3) in terms of scattering cross sections, the electron velocity distribution, and appropriate photochemical quantum yields.

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“…However, at low N 2 O pressure below 0.3 Torr the approximation of the constant ion mean free path is replaced with the approximation of the constant ion mobility in the cathode sheath. One may assume that at low pressure a considerable dissociation of N 2 O molecules via electron impact (Kline et al 1991) occurs with subsequent ionization of NO molecules formed. Positive NO + ions cannot experience charge exchange when colliding with N 2 O molecules because the ionization potential of NO molecules is 9.26 eV being less than the ionization potential of N 2 O molecules amounting to 12.89 eV (Rapp and Englander-Golden 1965).…”

Section: Resultsmentioning

confidence: 99%

Applicability of Child–Langmuir collision laws for describing a dc cathode sheath in N₂O

Lisovskiy¹,

Artushenko²,

Yegorenkov³

2013

J. Plasma Phys.

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It is established which of the Child-Langmuir collision law versions are most appropriate for describing the processes in the cathode sheath in the N 2 O. At low pressure (up to 0.3 Torr), the Child-Langmuir law version relating to the constant ion mobility holds. At N 2 O pressure values starting from 0.75 Torr and above, one has to employ the law version for which it is assumed that the ion mean free path within the cathode sheath is constant. In the intermediate pressure range (between 0.3 and 0.75 Torr), neither of the Child-Langmuir law versions gives a correct description of the cathode sheath of the glow discharge in the N 2 O.

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Diagnostics and modeling of RF discharge dissociation in N/sub 2/O

Cited by 46 publications

References 18 publications

Low-Pressure DC Air Plasmas. Investigation of Neutral and Ion Chemistry

Low-Pressure DC Air Plasmas. Investigation of Neutral and Ion Chemistry

Radio frequency plasma decomposition of ammonia: a comparison with radiation chemistry using the G value

Applicability of Child–Langmuir collision laws for describing a dc cathode sheath in N₂O

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Diagnostics and modeling of RF discharge dissociation in N/sub 2/O

Cited by 46 publications

References 18 publications

Low-Pressure DC Air Plasmas. Investigation of Neutral and Ion Chemistry

Low-Pressure DC Air Plasmas. Investigation of Neutral and Ion Chemistry

Radio frequency plasma decomposition of ammonia: a comparison with radiation chemistry using the G value

Applicability of Child–Langmuir collision laws for describing a dc cathode sheath in N2O

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Applicability of Child–Langmuir collision laws for describing a dc cathode sheath in N₂O