The calculation of electron density and temperature in Ar spectroscopic plasmas from continuum and line spectra

Decomposition of chlorobenzene as a model molecule of aromatic chlorinated compounds was studied in radiofrequency (RF) thermal plasma both in neutral and oxidative conditions. Optical emission spectroscopy (OES) was applied for the evaluation of the plasma excitation and molecular rotational-vibrational temperature. Atomic (C, H, O) and molecular (CH, OH, C 2 ) radicals were identified, while the morphology of the formed soot was characterized by electron microscopy. Organic compounds adsorbed on the surface of the soot after plasma processing were comprised of various polycyclic aromatic hydrocarbons (PAH) and chlorinated PAH molecules. Their amount was greatly affected by experimental conditions, especially the oxygen content and plate power. The higher input power reduced the ring number of the PAH molecules. Addition of oxygen significantly reduced the amount of both PAHs chlorinated PAH molecules but enhanced the formation of polychlorinated benzene compounds.

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“…Excitation temperature of the pure Ar plasma was found to be 9000-10000 K. This result is in good agreement with data published by others [22]. …”

Section: Log(i Ij λ Ij /G I F Ij ) = -E I /Kt Ex +C (C:constant)supporting

confidence: 92%

Decomposition of Chlorobenzene by Thermal Plasma Processing

Fazekas

Bódis

Keszler

et al. 2013

Plasma Chem Plasma Process

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“…The emission coefficient ε l can be expressed in terms of the electron temperature and density [13]:…”

Section: Plasma Temperaturementioning

confidence: 99%

“…By including the second ionization contribution to the continuum radiation, the continuum emission coefficient can be rewritten as [13,14]: …”

Section: Plasma Temperaturementioning

confidence: 99%

Laser–plasma interactions in fused silica cavities

Zeng

Mao

et al. 2004

Journal of Applied Physics

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The effect of laser energy on formation of a plasma inside a cavity was investigated. The temperature and electron number density of laser-induced plasmas in a fused silica cavity were determined using spectroscopic methods, and compared with laser ablation on a flat surface. Plasma temperature and electron number density during laser ablation in a cavity with aspect ratio of 4 increased faster with irradiance after the laser irradiance reached a threshold of 5 GW/cm 2 . The threshold irradiance of particulate ejection was lower for laser ablation in a cavity compared with on a flat surface; the greater the cavity aspect ratio, the lower the threshold irradiance. The ionization of silicon becomes saturated and the crater depths were increased approximately by an order of magnitude after the irradiance reached the threshold. Phase explosion was discussed to explain the large change of both plasma characteristics and mass removal when irradiance increased beyond a threshold value. Self-focusing of the laser beam was discussed to be responsible for the decrease of the threshold in cavities.

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“…However, it can be helpful to simplify the calculation of Te or to detect defects. For example, an alternative method to compute Te is the line-to-continuum ratio method (Bastiaans & Mangold, 1985). In this case, Te is calculated using the relation between a single emission line intensity (integrated over the line profile) l and the intensity of the adjacent background radiation (non-integrated) I c : …”

Section: Optical Methods For On-line Quality Assurance Of Welding Promentioning

confidence: 99%