An improved LTE model of a high pressure sulfur discharge

Johnston, C.W.; Heijden, H.W.P. van der; Hartgers, A.; Garloff, K.F.; Dijk, Jan van; Mullen, J.J.A.M. van der

doi:10.1088/0022-3727/37/2/009

Cited by 21 publications

(11 citation statements)

References 21 publications

(40 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…14 Considerable effort has also gone toward the development of radiative-transfer models for these sulfur discharges. 15,16 The B − X system is the S 2 analog of the Schumann-Runge system in the isovalent O 2 molecule and has been the subject of numerous experimental and theoretical studies. In 32 S 2 , the v = 0-9 levels of the B state lie below the first dissociation limit.…”

Section: Introductionmentioning

confidence: 99%

Fourier-transform-spectroscopic photoabsorption cross sections and oscillator strengths for the S2 BΣu−3−XΣg−3 system

Stark

Herde

Lyons

et al. 2018

The Journal of Chemical Physics

View full text Add to dashboard Cite

Photoabsorption cross sections and oscillator strengths for the strong, predissociating vibrational bands, v ≥ 11, in the S BΣu-3-XΣg-3(v,0) system are reported. Absorption measurements were undertaken on S vapor produced by a radio-frequency discharge through HS seeded in helium, and also in a two-temperature sulfur furnace, at temperatures of 370 K and 823 K, respectively. S column densities were determined in each source by combining experimental line strengths in low-v non-predissociating B - X bands (v < 7) with calculated line f-values based on measured radiative lifetimes and calculated branching ratios. The broad-band capabilities of two vacuum-ultraviolet Fourier-transform spectrometers, used with instrumental resolutions of 0.22 cm and 0.12 cm, respectively, allowed for simultaneous recordings of both non-predissociating and predissociating bands, thus placing the predissociating-band cross sections on a common absolute scale. Uncertainties in the final cross section datasets are estimated to be 15% for the 370-K vapor and 10% for the 823-K vapor. The experimental cross sections are used to inform a detailed predissociation model of the B(v) levels in Paper II [Lewis et al., J. Chem. Phys. 148, 244303 (2018)]. For astrophysical and other applications, this model can be adjusted simply to provide isotopologue-specific cross sections for a range of relevant temperatures.

show abstract

Section: Introductionmentioning

confidence: 99%

Fourier-transform-spectroscopic photoabsorption cross sections and oscillator strengths for the S2 BΣu−3−XΣg−3 system

Stark

Herde

Lyons

et al. 2018

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…In industrial condition, S 2 molecules can be seen in reactive ion etching process using SF 6 molecules [7]. Sulfur lamps contain S 2 molecules as an important ingredient [8]. Although electron collision with S 2 molecules is an important elementary process in these plasmas, there has been little work on this subject.…”

Section: Introductionmentioning

confidence: 99%

Electron impact excitations of S2 molecules

Tashiro

2008

Chemical Physics Letters

View full text Add to dashboard Cite

Low-energy electron impact excitations of S_2 molecules are studied using the fixed-bond R-matrix method based on state-averaged complete active space SCF orbitals. Integral cross sections are calculated for elastic electron collision as well as impact excitation of the 7 lowest excited electronic states. Also, differential cross sections are obtained for elastic collision and excitation of the a^1 Delta_g, b^1 Sigma_g^+ and B^3 Sigma_u^- states. The integrated cross section of optically allowed excitation of the B^3 Sigma_u^- state agrees reasonably well with the available theoretical result.Comment: 12 pages, 3 figures. Chemical Physics Letters, in pres

show abstract

“…The optical thickness therefore increases extensively during the evaporation of sulfur, as it is expected, since the number density of the molecules in the vapor becomes much larger. When the steady regime is reached, the laser red spot cannot be distinguished anymore on the screen strongly illuminated by the white light coming from the plasma, confirming that its core in operating condition is optically thick (optical depth is about 10 µm according to [12]). In contrast, the vapor around the plasma core remains transparent, since one can see the rear grid through it.…”

Section: Observationsmentioning

confidence: 99%

On the plasma confinement by acoustic resonance

et al. 2017

View full text Add to dashboard Cite

In an applied research project on the development of a pulsed microwave sulfur lamp prototype of 1 kW, we have discovered an amazing phenomenon in which the plasma forms a ball staying at the center of the bulb despite gravity, thus protecting the glass from melting. In this paper, it is shown that this results from an acoustic resonance in a spherical mode. Measurements of the plasma response to short pulses are presented showing beats at the spherical resonance. It is demonstrated that the beats could result from the simultaneous excitation of two normal modes with a frequency difference of approximately 1%. One of the two frequencies matches precisely the microwave pulses repetition, a little below 30 kHz. Thus this one is due to a forced oscillation, whereas the other one is due to a free oscillation. The phase velocity of sound was calculated as a function of temperature in order to find the series of temperatures at which a resonance would occur if the bulb were an isothermal solid sphere. The mean temperature inside the actual bulb was determined from the only doublet of this series, that has characteristic frequencies close enough to cause the observed beats. In addition, one of these two modes has a spherical symmetry that can explain the plasma ball formation. The obtained mean temperature is consistent with the direct measurements on the bulb surface as well as with the temperature in the core of a similar plasma found in the literature. We have also proposed a model of the resonance onset based on the acoustic dispersion and the sound amplification due to electromagnetic coupling. Key words. molecular plasma-pulsed microwave plasma-plasma confinement-acoustic resonanceacoustic dispersion-sound amplification due to electromagnetic coupling-plasma of sulfur-electrodeless light bulb-high-pressure lamps-light sources

show abstract

An improved LTE model of a high pressure sulfur discharge

Cited by 21 publications

References 21 publications

Fourier-transform-spectroscopic photoabsorption cross sections and oscillator strengths for the S2 BΣu−3−XΣg−3 system

Fourier-transform-spectroscopic photoabsorption cross sections and oscillator strengths for the S2 BΣu−3−XΣg−3 system

Electron impact excitations of S2 molecules

On the plasma confinement by acoustic resonance

Contact Info

Product

Resources

About