10.57647/j.jtap.2025.1902.21

Role of the atomic argon on the plasma characteristics of O2/N2 gas mixture

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  • Saeed Karimian1,
  • Sanaz Payandeh2,
  • Zahra Emam Bakhsh3,
  • Amir Falahat3,
  • Ali Barkhordari*2,
  1. Department of Physics, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
  2. Faculty of Physics, Shahid Bahonar University of Kerman, Kerman, Iran.
  3. Photonics Research Institute, Graduate University of Advanced Technology, Kerman, Iran.

Received: 2025-01-28

Revised: 2025-03-25

Accepted: 2025-04-03

Published 2025-04-27

Copyright (c) 2025 Saeed Karimian, Sanaz Payandeh, Zahra Emam Bakhsh, Amir Falahat, Ali Barkhordari (Author)

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This work is licensed under a Creative Commons Attribution 4.0 International License.

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1.
Karimian S, Payandeh S, Emam Bakhsh Z, Falahat A, Barkhordari A. Role of the atomic argon on the plasma characteristics of O2/N2 gas mixture. J Theor Appl phys. 2025 Apr. 27;19(2 (April 2025):1-15. Available from: https://oiccpress.com/jtap/article/view/16591
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Abstract

The current work conducts a detailed investigation on adding atomic argon to the O2/N2 plasma in direct current (DC) and radiofrequency (RF) atmospheric plasma jets (APJs) using Optical Emission Spectroscopy (OES). The plasma density, rotational, vibrational, and excitation temperatures are determined by studying emission spectra obtained near the DC and RF APJs plume. The NO and OH bands are seen in the emission spectrum. The three N2 vibrational bands and the Ar I spectral emission line intensities are used to calculate the vibrational and excitation temperatures. The emission intensity from argon ions increases with larger argon contributions in the Ar/O2/N2 gaseous mixture in both APJs. Furthermore, when the argon contribution to the mixture is high and nitrogen is greater than oxygen, the plasma electron density decreases as the rotational, vibrational, and excitation temperatures rise. However, for both the generated APJs, when oxygen contributes more than nitrogen and increases plasma electron density, the vibrational and rotational temperatures fall. However, larger input DC and RF powers result in higher plasma density and rotational,
vibrational, and excitation temperatures for both DC and RF APJs. Furthermore, the molecular oxygen and nitrogen dissociation rate increases as the amount of argon in the mixture increases.

Keywords

  • DC and RF APJs,
  • Ar/O2/N2 gas mixture,
  • Optical emission spectroscopy (OES),
  • Actinometry
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References

  1. M. Moisan, J. Barbeau, J. Moreau, S. Pelletier, M. Tabrizian, and Y. L’H. “Low-temperature sterilization using gas plasmas: a review of the experiments and an analysis of the inactivation mechanisms. ”. International journal of Pharmaceutics., 226(1-2):1–21, 2001. doi: 10.1016/S0378-5173(01)00752-9.
  2. S. Lerouge, M. R. Wertheimer, and L. H. Yahia. “Plasma sterilization: a review of parameters, mechanisms, and limitations.”. Plasmas and polymers, 6:175–88, 2001. doi: 10.1023/A:1013196629791.
  3. T. C. Montie, K. Kelly-Wintenberg, and J. R. Roth. “An overview of research using the one atmosphere uniform glow discharge plasma (OAUGDP) for sterilization of surfaces and materials.”. IEEE Transactions on plasma science, 28(1):41–50, 2000. doi: 10.1109/27.842860.
  4. M. Laroussi. “Low temperature plasma-based sterilization: overview and state-of-the-art. ”. Plasma processes and polymers, 2(5):391–400, 2005. doi: 10.1002/ppap.200400078.
  5. F. Rossi, O. Kylian, and M. Hasiwa. “Decontamination of surfaces by low pressure plasma discharges.”. Plasma Processes and Polymers, 3(6-7):431–42, 2006. doi: 10.1002/ppap.200600011.
  6. A. Barkhordari, S. Karimian, A. Rodero, D. A. Krawczyk, S. I. Mirzaei, and A. Falahat. “Carbon dioxide decomposition by a parallel-plate plasma reactor: Experiments and 2-D modelling. ”. Applied Sciences, 11(21):10047, 2021. doi: 10.3390/app112110047.
  7. A. Von Keudell, P. Awakowicz, J. Benedikt, V. Raballand, A. Yanguas-Gil, J. Opretzka, C. Flotgen, R. Reuter, L. Byelykh, H. Halfmann, and K. Stapelmann. “Inactivation of bacteria and biomolecules by low-pressure plasma discharges.”.
  8. H. Yu, Z. L. Xiu, C. S. Ren, J. L. Zhang, D. Z. Wang, Y. N. Wang, and T. C. Ma. “Inactivation of yeast by dielectric barrier discharge (DBD) plasma in helium at atmospheric pressure.”. IEEE transactions on plasma science, 33(4):1405–9, 2005. doi: 10.1109/TPS.2005.851961.
  9. A. Barkhordari, S. I. Mirzaei, A. Falahat, and A. Rodero. “Numerical and experimental study of an Ar/CO2 plasma in a point-to-plane reactor at atmospheric pressure.”. Spectrochimica acta part B: Atomic spectroscopy., 177:106048, 2021. doi: 10.1016/j.sab.2020.106048.
  10. O. Kylian, M. Hasiwa, and F. Rossi. “ Effect of low-pressure microwave discharges on pyrogen bioactivity.”. IEEE transactions on plasma science, 34(6):2606–10, 200. doi: 10.1109/TPS.2006.885093.
  11. M. Hasiwa, O. Kylian, and F. Hartung, T. Rossi. “Removal of immune-stimulatory components from surfaces by plasma discharges.”. Innate Immunity, 14(2):89–97, 2008. doi: 10.1177/175342590708.
  12. H. C. Baxter, G. A. Campbell, A. G. Whittaker, A. C. Jones, A. Aitken, A. H. Simpson, M. Casey, L. Bountiff, L. Gibbard, and R. L. Baxter. “Elimination of transmissible spongiform encephalopathy infectivity and decontamination of surgical instruments by using radio-frequency gas-plasma treatment. ”. Journal of general virology, 86(8):2393–9, 2005. doi: 10.1099/vir.0.81016-0.
  13. H. C. Baxter, P. R. Richardson, G. A. Campbell, V. I. Kovalev, R. Maier, J. S. Barton, A. C. Jones, G. DeLarge, M. Casey, and R. L. Baxter. “ Application of epifluorescence scanning for monitoring the efficacy of protein removal by RF gas–plasma decontamination.”. New Journal of Physics, 11(11):115028, 2009. doi: 10.1088/1367- 2630/11/11/115028.
  14. X. T. Deng, J. J. Shi, and M. G. Kong. “Protein destruction by a helium atmospheric pressure glow discharge: capability and mechanisms.”. Journal of applied physics, 101(7), 2007. doi: 10.1063/1.2717576.
  15. G. Ceccone, D. Gilliland, O. Kylian, and F. Rossi. “ Experimental study of effect of low-pressure O2: H2 microwave discharge on protein films.”. Czechoslovak Journal of Physics, 56:B672–7, 2006. doi: 10.1007/s10582-006-0269-1.
  16. S. Karimian, S. Falahat, Z. E. Bakhsh, M. J. Rad, and A. Barkhordari. “A comparative study on predicting the characteristics of plasma activated water: artificial neural network (ANN) & support vector regression (SVR).”. Journal of Theoretical and Applied Physics, 18(4), 2024. doi: 10.57647/j.jtap.2024.1804.48.
  17. A. Barkhordari, S. Karimian, S. Shahsavari, D. Krawczyk, and A. Rodero. “Influence of the argon admixture on the reactive oxide species formation inside an atmospheric pressure oxygen plasma jet.”. Scientific Reports, 14(1):3425, 2024. doi: 10.1038/s41598-024-54111-y.
  18. K. Stapelmann, O. Kylian, B. Denis, and F. Rossi. “On the application of inductively coupled plasma discharges sustained in Ar/O2/N2 ternary mixture for sterilization and decontamination of medical instruments.”. Journal of Physics D: Applied Physics., 41(19):192005, 2008. doi: 10.1088/0022-3727/41/19/192005.
  19. O. Kylian and F. Rossi. “Sterilization and decontamination of medical instruments by low-pressure plasma discharges: application of Ar/O2/N2 ternary mixture.”. Journal of Physics D: Applied Physics., 42(8):085207, 2009. doi: 10.1088/0022-3727/42/8/08520.
  20. N. Munakata, K. Hidea, K. Kobayashi, A. Ito, and T. Ito. “Action spectra in ultraviolet wavelengths (150-250 nm) for inactivation and mutagenesis of bacillus subtilis spores obtained with synchrotron radiation.”. Photochemistry and photobiology, 44(3):385–90, 1986. doi: 10.1111/j.1751-1097.1986.tb04680.x.
  21. M. K. Boudam and M. Moisan. “Synergy effect of heat and UV photons on bacterial-spore inactivation in an N2–O2 plasma-afterglow sterilizer.”. Journal of physics D: applied physics., 43(29):295202, 2010. doi: 10.1088/0022-3727/43/29/295202.
  22. Y. Yasuda, S. Zaima, T. Kaida, and Y. Koide. “Mechanisms of silicon oxidation at low temperatures by microwave-excited O2 gas and O2-N2 mixed gas. ”. Journal of applied physics, 67(5):2603–7, 1990. doi: 10.1063/1.345465.
  23. A. Vesel, M. Kolar, N. Recek, K. Kutasi, K. Stana-Kleinschek, and M. Mozetic. “Etching of blood proteins in the early and late flowing afterglow of oxygen plasma.”. Plasma Processes and Polymers, 11(1):12–23, 2014. doi: 10.1002/ppap.201300067.
  24. K. Kutasi, C. Noel, T. Belmonte, and V. Guerra. “Tuning the afterglow plasma composition in Ar/N2/O2 mixtures: characteristics of a flowing surface-wave microwave discharge system.”. Plasma Sources Science and Technology, 25(5):055014, 2016. doi: 10.1088/0963-0252/25/5/055014.
  25. S. Greenfield, P. B. Smith, H. M. McGeachin, R. M. Dagnall, B. L. Sharp, and D. R. Marriott. “ Plasma excitation in spectrochemical analysis.”. Proceedings of the Society for Analytical Chemistry, 10(4):89–91, 1973. doi: 10.1039/SA9731000089.
  26. Bessoth F. G., O. P. Naji, J. C. Eijkel, and A. Manz. “Towards an on-chip gas chromatograph: the development of a gas injector and a dc plasma emission detector.”. Journal of Analytical Atomic Spectrometry, 17(8):794–9, 2002. doi: 10.1039/B203180A.
  27. C. G. Wilson and Y. B. Gianchandani. “Spectral detection of metal contaminants in water using an on-chip microglow discharge.”. IEEE Transactions on Electron Devices, 49(12):2317–22, 2002. doi: 10.1109/TED.2002.805608.
  28. J. Franzke, K. Kunze, M. Miclea, and K. Niemax. “Microplasmas for analytical spectrometry.”. Journal of Analytical Atomic Spectrometry, 18(7):802–7, 2003. doi: 10.1039/B300193H.
  29. F. J. Andrade, W. C. Wetzel, G. C. Chan, M. R. Webb, G. Gamez, S. J. Ray, and G. M. Hieftje. “A new, versatile, direct-current helium atmospheric-pressure glow discharge.”. Journal of analytical atomic spectrometry, 21(11):1175–84, 2006. doi: 10.1039/B607544D.
  30. A. Barkhordari, A. Ganjovi, I. Mirzaei, A. Falahat, and M. N. Rostami Ravari. “A pulsed plasma jet with the various Ar/N2 mixtures. ”. Journal of Theoretical and Applied Physics, 11:301–12, 2017. doi: 10.1007/s40094-017-0271-y.
  31. A. Barkhordari, A. Ganjovi, I. Mirzaei, and A. Falahat. “Study of the physical discharge properties of a Ar/O 2 DC plasma jet. ”. Indian Journal of Physics, 92:1177–86, 2018. doi: 10.1007/s12648-018-1197-1.
  32. A. Barkhordari and A. Ganjovi. “Technical characteristics of a DC plasma jet with Ar/N2 and O2/N2 gaseous mixtures.”. Chinese Journal of Physics, 57:465–78, 2019. doi: 10.1016/j.cjph.2018.10.017.
  33. A. Falahat, A. Ganjovi, M. Taraz, M. R. Ravari, and A. Shahedi. “ Optical characteristics of a RF DBD plasma jet in various Ar/O2 mixtures.”. Pramana, 90(2):27, 2018. doi: 10.1007/s12043-018-1520-6.
  34. A. Barkhordari, A. Ganjovi, and S. I. Mirzaei. “Experimental study of a positive DC corona jet working with Ar/CO2 gaseous mixture.”. Pramana, 95:1–3, 2021. doi: 10.1007/s12043-021-02090-4.
  35. A. Morisako, M. Matsumoto, S. Takei, and T. Yamazaki. “Effect of substrate temperature on magnetic properties of strontium ferrite thin films.”. IEEE Transactions on Magnetics., 33(5):3100–2, 1997. doi: 10.1109/20.617857.
  36. J. Zhang, X. Li, W. Yang, W. Yan, D. Wei, Y. Liu, and G. Yan. “The effect of the length to diameter ratio on capillary discharge plasmas.”. Physics of Plasmas, 25(10), 2018. doi: 10.1063/1.5041781.
  37. C. Tendero, C. Tixier, P. Tristant, J. Desmaison, and P. Leprince. “Atmospheric pressure plasmas: A review. ”. Spectrochimica Acta Part B: Atomic Spectroscopy., 61(1):2–30, 2006. doi: 10.1016/j.sab.2005.10.003.
  38. H. X. Deng, X. L. Gong, and L. H. Wang. “Development of an adaptive tuned vibration absorber with magnetorheologicalelastomer.”. Smart materials and structures, 15(5):N111, 2006. doi: 10.1088/0964-1726/15/5/N02.
  39. A. Fridman and G. Friedman. “Plasma Medicine”. Begell House, US,, 1:21, 2010.
  40. J. S. Chang, P. A. Lawless, and T. Yamamoto. “Corona discharge processes. ”. IEEE Transactions on plasma science, 19(6):1152–66, 1991. doi: 10.1109/27.125038.
  41. F. Grum and L. F. Costa. “Spectral emission of corona discharges.”. Applied Optics, 15(1):76–9, 1976. doi: 10.1364/AO.15.000076.
  42. M. Goldman, A. Goldman, and R. S. Sigmond. “The corona discharge, its properties and specific uses.”. Pure and Applied Chemistry, 57(9):1353–62, 1985. doi: 10.1351/pac198557091353.
  43. A. Barkhordari, S. I. Mirzaei, A. Falahat, D. A. Krawczyk, and A. Rodero. “Experimental study of a rotating electrode plasma reactor for hydrogen production from liquid petroleum gas conversion.”. Applied Sciences, 12(8):4045, 2022. doi: 10.3390/app12084045.
  44. Z. Weiss. “Quantitative depth profile analysis by glow discharge optical emission spectrometry: an alternative approach. ”. Journal of Analytical Atomic Spectrometry, 10(10):891–5, 1995. doi: 10.1039/JA9951000891.
  45. K. Hensel, S. Katsura, and A. Mizuno. “DC microdischarges inside porous ceramics. ”. IEEE Transactions on Plasma Science, 33(2):574–5, 2005. doi: 10.1109/TPS.2005.845389.
  46. Z. Machala, M. Janda, K. Hensel, I. Jedlovsky, L. Lestinska, V. Foltin, V. Martisovits, and M. Morvova. “Emission spectroscopy of atmospheric pressure plasmas for bio-medical and environmental applications.”. Journal of Molecular Spectroscopy, 243(2):194–201, 2007. doi: 10.1016/j.jms.2007.03.001.
  47. K. Shimizu and T. Oda. “Emission spectrometry for discharge plasma diagnosis. ”. Science and Technology of Advanced Materials, 2(3-4):577, 2001. doi: 10.1016/S1468-6996(01)00140-1.
  48. L. G. Piper, L. M. Cowles, and W. T. Rawlins. “State-to-state excitation of NO (A2 P +, v′= 0, 1, 2) by N2(A 3P + u, v′= 0, 1, 2).”. The Journal of chemical physics, 85(6):3369–78, 1986. doi: 10.1063/1.450958.
  49. Z. Machala, M. Morvova, E. Marode, and I. Morva. “Removal of cyclohexanone in transition electric discharges atatmospheric pressure.”. Journal of Physics D: Applied Physics, 33(24):3198, 2000. doi: 10.1088/0022-3727/33/24/313.
  50. D. Nie, W. Wang, D. Yang, H. Shi, Y. Huo, and L. Dai. “Optical study of diffuse bi-directional nanosecond pulsed dielectric barrier discharge in nitrogen.”. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy., 79(5):1896–903, 2011. doi: 10.1016/j.saa.2011.05.083.
  51. P. Bruggeman, F. Iza, P. Guns, D. Lauwers, M. G. Kong, Y. A. Gonzalvo, C. Leys, and D. C. Schram. “Electronic quenching of OH (A) by water in atmospheric pressure plasmas and its influence on the gas temperature determination by OH (A–X) emission.”. Plasma Sources Science and Technology., 19(1):015016, 2009. doi: 10.1088/0963-0252/19/1/015016.
  52. A. Bogaerts and R. Gijbels. “Fundamental aspects and applications of glow discharge spectrometric techniques.”. Spectrochimica Acta Part B: Atomic Spectroscopy, 53(1):1–42, 1998. doi: 10.1016/S0584-8547(97)00122-5.
  53. S. Bockel, J. Amorim, G. Baravian, A. Ricard, and P. Stratil. “ A spectroscopic study of active species in DC and HF flowing discharges in-and Ar–mixtures. ”. Plasma Sources Science and Technology., 5(3):567, 1666. doi: 10.1088/0963-0252/5/3/026.
  54. S. D. Popa. “Influence of pressure on spectral intensities in a flowing nitrogen glow discharge.”. Journal of Physics D: Applied Physics, 29(2):416, 1996. doi: 10.1088/0022-3727/29/2/019.
  55. K. Behringer and U. Fantz. “Spectroscopic diagnostics of glow discharge plasmas with non-Maxwellian electron energy distributions.”. Journal of Physics D: Applied Physics, 27(10):2128, 1994. doi: 10.1088/0022-3727/27/10/021.
  56. D. Wang, D Zhao, K. Feng, X. Zhang, D. Liu, and S. Yang. “The cold and atmospheric-pressure air surface barrier discharge plasma for large-area sterilization applications.”. Applied Physics Letters, 98(16), 2011. doi: 10.1063/1.3582923.
  57. N. K. Bibinov, A. A. Fateev, and K. Wiesemann. “On the influence of metastable reactions on rotational temperatures indielectric barrier discharges in He-N2 mixtures.”. Journal of Physics D: Applied Physics, 34(12):1819, 2001. doi: 10.1088/0022-3727/34/12/309.
  58. V. Milosavljevic and P. J. Cullen. “Spectroscopic investigation of a dielectric barrier discharge in modified atmosphere packaging. ”. The European Physical Journal Applied Physics, 80(2):20801, 2017. doi: 10.1051/epjap/2017170201.
  59. V. M. Donnelly. “Plasma electron temperatures and electron energy distributions measured by trace rare gases optical emission spectroscopy.”. Journal of Physics D: Applied Physics., 37(19):R217, 2004. doi: 10.1088/0022-3727/37/19/R01.
  60. J. B. Boffard, C. C. Lin, and C. A. DeJoseph Jr. “Application of excitation cross sections to optical plasma diagnostics.”. Journal of Physics D: Applied Physics, 37(12):R143, 2004. doi: 10.1088/0022-3727/37/12/R01.
  61. G. Norlen. “Wavelengths and energy levels of Ar I and Ar II based on New Interferometric Measurements in the Region 3 400-9 800 ˚A.”. Physica Scripta, 8(6):249, 1973. doi: 10.1088/0031-8949/8/6/007.
  62. A. Lofthus and P. H. Krupenie. “The spectrum of molecular nitrogen.”. Journal of physical and chemical reference Data, 6(1):113–307, 1977. doi: 10.1063/1.555546.
  63. H. R. Griem. “Plasma Spectroscopy ”. McGraw-Hill, New York, 1:386, 1964.
  64. T. G. Owano, M. H. Gordon, and C. H. Kruger. “Measurements of the radiation source strength in argon at temperatures between 5000 and 10 000 K.”. Physics of Fluids B: Plasma Physics, 2(12):3184–90, 1990. doi: 10.1063/1.859228.
  65. M. D. Calzada, A. Rodero, A. Sola, and A. Gamero. “Excitation kinetic in an argon plasma column produced by a surface wave at atmospheric pressure.”. Journal of the Physical Society of Japan, 65(4):948–54, 1996. doi: 10.1143/JPSJ.65.948.
  66. T. Fujimoto and R. W. McWhirter. “Validity criteria for local thermodynamic equilibrium in plasma spectroscopy.”. Physical Review A, 42(11):6588, 1990. doi: 10.1103/PhysRevA.42.6588.
  67. C. O. Laux, R. J. Gessman, C. H. Kruger, F. Roux, F. Michaud, and S. P. Davis. “Rotational temperature measurements in air and nitrogen plasmas using the first negative system of N2+.”. Journal of Quantitative Spectroscopy and Radiative Transfer., 68(4):473–82, 2001. doi: 10.1016/S0022-4073(00)00083-2.
  68. G. Herzberg. “ Molecular Spectra and Molecular Structure I: Spectra of Diatomic Molecules”. Van Nostrand, New York, , 1950.
  69. D. R. Lide. “Handbook of Chemistry and Physics ”. CRC Press, Boca Raton, , 2001.
  70. “National Institute of Standards and Technology”. NIST: Atomic Spectra Data Base (Gaithersburg, MD: NIST Physics Laboratory), , 1979-2008.
  71. D. H. Winicur and J. L. Fraites. “Electronic-energy exchange cross sections for Ar*(3 P) and N 2 (X 1 P g+). ”. The Journal of Chemical Physics, 61(4):1548–53, 1974. doi: 10.1063/1.1682099.
  72. J. Levaton, J. Amorim, and D. Franco. “Experimental and calculated N (4S) temporal density profile in the N2 flowing post-discharge. ”. Journal of Physics D: Applied Physics, 38(13):2204, 2005. doi: 10.1088/0022-3727/38/13/019.
  73. G. G. Raju. “Collision cross sections in gaseous electronics part I: what do they mean.”. IEEE electrical insulation magazine, 22(4):5–23, 2006. doi: 10.1109/MEI.2006.1678354.
  74. R. S. Chang and D. W. Setser. “Radiative lifetimes and two-body deactivation rate constants for Ar (3 p 5, 4 p) and Ar (3 p 5, 4 p′) states.”. The Journal of Chemical Physics, 69(9):3885–97, 1978. doi: 10.1063/1.437126.
  75. M. Qian, C. Ren, D. Wang, J. Zhang, and G. Wei. “Stark broadening measurement of the electron density in an atmospheric pressure argon plasma jet with double-power electrodes. ”. Journal of Applied Physics, 107(6), 2010. doi: 10.1063/1.3330717.
  76. A. Y. Nikiforov, C. Leys, M. A. Gonzalez, and J. L. Walsh. “Electron density measurement in atmospheric pressure plasma jets: Stark broadening of hydrogenated and non-hydrogenated lines.”. Plasma Sources Science and Technology, 24(3):034001, 2015. doi: 10.1088/0963-0252/24/3/034001.
  77. J. M. Mermet. “Inductively Coupled Plasma Emission Spectroscopy edited by PWJM Boumans”. Wiley, New York, , 1987.
  78. C. O. Laux, T. G. Spence, C. H. Kruger, and R. N. Zare. “Optical diagnostics of atmospheric pressure air plasmas.”. Plasma Sources Science and Technology, 12(2):125, 2003. doi: 10.1088/0963-0252/12/2/301.
  79. S. G. Belostotskiy, T. Ouk, V. M. Donnelly, D. J. Economou, and N. Sadeghi. “Gas temperature and electron density profiles in an argon dc microdischarge measured by optical emission spectroscopy.”. Journal of applied physics, 107(5), 2010. doi: 10.1063/1.3318498.
  80. F. J. Mehr and M. A. Biondi. “Electron-temperature dependence of electron-ion recombination in Argon.”. Physical Review, 176(1):322, 1968. doi: 10.1103/PhysRev.176.322.
  81. M. A. Gigosos and V. Cardenoso. “New plasma diagnosis tables of hydrogen Stark broadening including ion dynamics. ”. Journal of Physics B: Atomic, Molecular and Optical Physics, 29(20):4795, 1996. doi: 10.1088/0953-4075/29/20/029.
  82. D. Staack, B. Farouk, A. Gutsol, and A. Fridman. “Characterization of a dc atmospheric pressure normal glow discharge. ”. Plasma Sources Science and Technology, 14(4):700, 2005. doi: 10.1088/0963-0252/14/4/009.
  83. N. Haraki, S. Nakano, S. Ono, and S. Teii. “Oxygen radical density measurement in O2–N2 gas mixture plasma by means of a thin platinum wire. ”. Electrical Engineering in Japan, 149(4):14–20, 2004. doi: 10.1002/eej.20018.
  84. J. C. Thomaz, J. Amorim, and C. F. Souza. “Validity of actinometry to measure N and H atom concentration in N2-H2 direct current glow discharges. ”. Journal of Physics D: Applied Physics, 32(24):3208, 1999. doi: 10.1088/0022-3727/32/24/317.
  85. M. A. Lieberman and A. J. Lichtenberg. “Principles of Plasma Discharge and Materials Processing”. Wiley, New York, 1994, 1:487.
  86. J. T. Gudmundsson and E. G. Thorsteinsson. “Oxygen discharges diluted with argon: dissociation processes.”. Plasma Sources Science and Technology, 16(2):399, 2007. doi: 10.1088/0963-0252/16/2/025.