Measurements of cross sections for electron-impact excitation into the metastable levels of argon and number densities of metastable argon atoms

Schappe, R. Scott; Schulman, M.B.; Anderson, L. W.; Lin, Chun C.

doi:10.1103/physreva.50.444

Cited by 37 publications

(25 citation statements)

References 29 publications

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“…where σ is the collision cross section for each reaction process in Table 1 , and the collision cross sections data for the Ar gas are referred to in refs 38 , 44 , 45 , 46 , 47 , 48 , 49 . The general EEDF can be written as follows 50 :…”

Section: Methodsmentioning

confidence: 99%

Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment and Modeling

Lee

Chung

2015

Sci Rep

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Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics.

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Section: Methodsmentioning

confidence: 99%

Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment and Modeling

Lee

Chung

2015

Sci Rep

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“…This review showed clearly that there is much more information on excitation from the ground state into the metastable states than on excitation out of these levels. Since then there have been important additions to the published cross section data for excitation from the ground state to the first and second groups of energy levels, with a number of notable contributions from Lin and Anderson and their co-workers [10][11][12], Mityureva and Smirnov [13], and others. These cross sections still show some variation but a great deal of progress has been made, as witnessed by the availability of data from a number of high-resolution studies of the sharp resonances which appear on these cross section curves, e.g.…”

Section: Introductionmentioning

confidence: 99%

The application of CW laser collisionally induced fluorescence modelling to determine neon excited-state electron collisional rate coefficients

Borthwick¹,

Paterson²,

Smith

et al. 2000

J. Phys. B: At. Mol. Opt. Phys.

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We describe a method for the determination of rate coefficients for collisional excitation out of the 1s states of a noble gas using continuous-wave laser collisionally induced fluorescence (CW LCIF, i.e. fluorescence from an upper level which is not that of the laser transition). The intensity of CW LCIF lines from an upper 2p level that is strongly coupled to an influential 1s level is dominated by the electron collisional rate out of that level. By an appropriate choice of LCIF line we fit our recently published theory to experimental observations to determine a set of electron collisional direct 1s mixing and 1s-2p excitation rate coefficients. The values of coefficients determined in this way show very good agreement with those which have been calculated using cross section data from the literature with the measured electron temperature. For cases where accurate cross section data are available for the 1s-2p transitions CW LCIF diagnostics should, via these rate coefficients, provide reliable values of the bulk electron temperature.

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“…So it is worth mentioning that an argon atom can be theoretically be excited to each of the four sub energy levels shown in figure 2 through inelastic collision, which is not restricted by the selection rule of radiation jump. The probability for a specific argon atom being excited to which sub energy level depends on the velocity distribution of the moving electrons and the excitation cross section of each sub energy level [17].…”

Section: The First Excitation Energy State Of Argon Atomsmentioning

confidence: 99%

“…However, all the excited atoms undergo de-excitation following the selection rule no matter which way they are excited. The de-excitation of a meta-stable atom from the sub energy levels 1s 3 and 1s 5 with a lifetime in order of ∼10 −3 s is forbidden by the selection rule, whereas the sub energy levels 1s 2 and 1s 4 de-excite within a lifetime in the order of ∼10 −8 s [17]. Take one of the four sub energy levels in the first excitation energy state of argon atoms, for example the sub energy level 1s 2 of 11.83 eV.…”

Section: The First Excitation Energy State Of Argon Atomsmentioning

confidence: 99%

From macro-measure of Franck–Hertz curves to micro-collisions between electrons and argon atoms

Huang¹,

Lü²,

Liu³

et al. 2020

Eur. J. Phys.

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A Franck–Hertz experiment is adopted in our undergraduate laboratory by using a cylindrical tetrode tube filled with argon vapor. The Franck–Hertz curves, i.e. the variation of the anode current via the accelerating voltage, are experimentally measured, and the key roles of the filament voltage, the control voltage, and the retarding voltage played in the experiments are studied. Diagrams of the micro-elastic/inelastic collisions between the electrons and argon atoms, which are of significance for students to build a connection between the macroscopic measurements and microscopic collisions occurring inside the Franck–Hertz tube, are schematically presented based on the experimental results. The peak/valley interval in the experimental Franck–Hertz curves of argon vapor increases as the accelerating voltage increases. The results further suggest that the lowest excitation energy of an argon atom cannot be exactly derived from the experimental results since all the four sub energy levels within the first excitation energy state of the argon atom are involved in the inelastic electron–atom collisions.

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Measurements of cross sections for electron-impact excitation into the metastable levels of argon and number densities of metastable argon atoms

Cited by 37 publications

References 29 publications

Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment and Modeling

Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment and Modeling

The application of CW laser collisionally induced fluorescence modelling to determine neon excited-state electron collisional rate coefficients

From macro-measure of Franck–Hertz curves to micro-collisions between electrons and argon atoms

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