Analysis of the He(3
                    <sup>3</sup>
                    S)-He(2
                    <sup>3</sup>
                    P) line profile obtained in dense helium plasma

Allard, N. F.; Deguilhem, Benjamin; Gadéa, Florent Xavier; Bonifaci, Nelly; Denat, А.

doi:10.1209/0295-5075/88/53002

Cited by 9 publications

(6 citation statements)

References 32 publications

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“…A detailed description of the triplet 3s-2p line at 706 nm has been given by Allard et al (2009) and Allard et al (2011). The singlet line at 728 nm in emission has also been investigated by Li (2008) for a large range of He densities and temperatures of the order of 300 K. While we observe the same general shape for the singlet line, the important feature of these lines is the development of a blue wing.…”

Section: Quasi-molecular Line Satellites For the 3s-2p Transitionssupporting

confidence: 55%

“…Very recently, significant progress in the description of He 2 singlet and triplet potential energies has been achieved (Allard et al 2009;Dell'Angelo et al 2012;Bonifaci et al 2012).…”

Section: He 2 Molecular Potential Energymentioning

confidence: 99%

“…The analysis and interpretation of these experimental spectra require the use of a suitable theoretical framework with the most accurate He 2 molecular potentials. Allard et al (2009) presented the first calculations of He-He collisional profiles due to the triplet 2p-3s transitions in a unified line-shape semiclassical theory that uses ab initio molecular potentials. The excellent agreement seen in Fig.…”

Section: Study Of the Line Profile Due To The 2p-3s Transitionsmentioning

confidence: 99%

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Blue satellites on He lines due to He-He collisions

Allard¹,

Deguilhem²,

Monari³

et al. 2013

A&A

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The shape and broadening of He lines affects radiative transport in dense, He-rich, stellar atmospheres. At wavelengths inaccessible for direct observation, we rely on theoretical calculations of self-broadening to support stellar structure and spectral modeling. In this work, we examine lines of He due to 1s-2p and 2p-3s transitions. The line profiles are analyzed in terms of a unified theory of spectral line broadening using ab initio potential energies that have been recently determined. For temperatures up to 20 000 K, the linear dependence of width and shift on gas density and the non-linear dependence on temperature of the Lorentzian core of the resonance line are described. Beyond the conventional symmetrical Lorentzian core, we show that they are asymmetrical and have significant additional contributions on the short wavelength side. This blue asymmetry is a consequence of maxima in the corresponding He 2 potential energy difference curves at short and intermediate internuclear distance. Over a limited range of density and temperature, laboratory measurements in the visible and near infrared can be used to validate the potentials that underlie the spectral line profile theory, which is useful for modeling spectra over the extreme ranges of temperature and density encountered in stellar and planetary atmospheres.

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Section: Quasi-molecular Line Satellites For the 3s-2p Transitionssupporting

confidence: 55%

“…Very recently, significant progress in the description of He 2 singlet and triplet potential energies has been achieved (Allard et al 2009;Dell'Angelo et al 2012;Bonifaci et al 2012).…”

Section: He 2 Molecular Potential Energymentioning

confidence: 99%

Section: Study Of the Line Profile Due To The 2p-3s Transitionsmentioning

confidence: 99%

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Blue satellites on He lines due to He-He collisions

Allard¹,

Deguilhem²,

Monari³

et al. 2013

A&A

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“…Depending on the temperature, a large part of the line profile in the region below the SVP is red-shifted. Our observations are important as a benchmark for theory [64][65][66][67][68][69][70] and will contribute to a better understanding of collisional processes, including in the atmosphere of the sun, and other stars and exoplanets [67][68][69][70][71][72][73][74][75][76]. Our studies are also relevant to an understanding of micro-solvation.…”

Section: Introductionmentioning

confidence: 73%

Atomic fluorescence emitted from a corona discharge in helium above and below saturated vapour pressure

et al. 2018

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Abstract.A new apparatus was constructed to investigate the visible and near infrared fluorescence spectroscopy of electronically excited helium over a wide range of pressures and temperatures, covering both the gaseous and liquid phases. To achieve sufficient throughput, increased sensitivity was established by employing a micro-discharge cell and a high performance lens system that allows for a large collection solid angle. With this set-up, several thousand spectra were recorded. The atomic 3s1 S → 2p 1 P and 3s 3 S → 2p 3 P atomic transitions showed line shifts, spectral broadening and intensity changes that were dependent in magnitude on pressure, temperature and thermodynamic phase. While in the gas phase the lines showed little dependency on the discharge cell temperature, the opposite was observed for the liquid phase, suggesting that a significant number of atoms were solvated. Triplet lines were up to a factor of 50 times stronger in intensity than the singlet lines, depending on pressure. When taking the particle density into account, this effect was stronger in the gas phase than in the liquid phase of helium. This was attributed to the recombination of He2 + , He3 + and He4 + with electrons, which is facilitated in the gas phase because of the significantly higher mobility.

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“…(Allard et al 2009b) and Hα by H (Allard et al 2008). He: self broadening of line 3s 3 S-2p 3 P (Allard et al 2009c, Allard et al 2011). Li: self broadening of resonance line (Reggami et al 2009); resonance line broadened by He (Peach & Whittingham 2009, Peach 2010a, Peach 2010b); 2s-3d transition broadened by Ne and Ar (Rosenberry & Stewart 2011).…”

Section: Broadening By Neutral Atoms and Moleculesmentioning

confidence: 99%

Division Xii / Commission 14 / Working Group Collision Processes

Peach¹,

Dimitrijević²

2011

Proc. IAU

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Research in atomic and molecular collision processes and spectral line broadening has been very active since our last report, Peach, Dimitrijević & Stancil 2009. Given the large volume of the published literature and the limited space available, we have attempted to identify work most relevant to astrophysics. Since our report can not be comprehensive, additional publications can be found in the databases at the web addresses listed in the final section. Elastic and inelastic collisions among electrons, atoms, ions, and molecules are included and charge transfer can be very important in collisions between heavy particles.

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Analysis of the He(3 ³ S)-He(2 ³ P) line profile obtained in dense helium plasma

Cited by 9 publications

References 32 publications

Blue satellites on He lines due to He-He collisions

Blue satellites on He lines due to He-He collisions

Atomic fluorescence emitted from a corona discharge in helium above and below saturated vapour pressure

Division Xii / Commission 14 / Working Group Collision Processes

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Analysis of the He(3 3 S)-He(2 3 P) line profile obtained in dense helium plasma

Cited by 9 publications

References 32 publications

Blue satellites on He lines due to He-He collisions

Blue satellites on He lines due to He-He collisions

Atomic fluorescence emitted from a corona discharge in helium above and below saturated vapour pressure

Division Xii / Commission 14 / Working Group Collision Processes

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Product

Resources

About

Analysis of the He(3 ³ S)-He(2 ³ P) line profile obtained in dense helium plasma