Stimulated emission cross section of H2 dissociation transition

Cohn, Arthur; Marcucci, M.

doi:10.1063/1.1662489

Cited by 3 publications

(4 citation statements)

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“…It is quite obvious that, when ε-dependences of the cross-sections have similar shapes, the ratio of the rate coefficients is less sensitive to the near-threshold region for F (ε) with a high content of fast enough electrons. To check the tendency we calculated the ratios for a Maxwellian distribution with an electron temperature of T e = 1 − 10 eV and the cross 14 Measurements in VUV are possible in principle, but they are not typical in most gas discharge and plasma technology applications due to their technical complexity and the difficulties in the sensitivity calibration and the spatial resolution.…”

Section: 8) So We Detected Only a Part Of The Continuum Emissionmentioning

confidence: 99%

“…For H 2 molecule the values of A av ′ b (λ) should be considered as well-known nowadays because they have been calculated in several works [1,[5][6][7]14] and checked experimentally [1,4], being in rather good agreement [7]. We used the results of [6] shown in Table I.…”

Section: Intensities Of H 2 Bands and Vibrational Temperature A Conti...mentioning

confidence: 99%

“…So we detected only a part of the continuum emission. 14 The rest should be obtained by some extrapolation. In pure hydrogen discharge plasma the vibrational temperature is usually rather low and the Eqs.…”

Section: Estimation Of the Rate Of Electron Impact Dissociationmentioning

confidence: 99%

“…They were stimulated by molecular spectroscopy and quantum chemistry [1][2][3][4][5][6][7], investigations of hydrogen containing plasmas [8][9][10] and astrophysics [11,12]. Since the first work of Houtermans [13] the a 3 Σ + g → b 3 Σ + u transition has been studied as a possible laser system (see [14][15][16][17] and Refs. therein).…”

Section: Introductionmentioning

confidence: 99%

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uv continuum emission and diagnostics of hydrogen-containing nonequilibrium plasmas

Lavrov

Melnikov

Käning³

et al. 1999

Phys. Rev. E

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For the first time the emission of the radiative dissociation continuum of the hydrogen molecule (a 3 Σ + g → b 3 Σ + u electronic transition) is proposed to be used as a source of information for the spectroscopic diagnostics of non-equilibrium plasmas. The detailed analysis of excitation-deactivation kinetics, rate constants of various collisional and radiative transitions and fitting procedures made it possible to develop two new methods of diagnostics of: (1) the ground X 1 Σ + g state vibrational temperature T vib from the relative intensity distribution, and (2) the rate of electron impact dissociation (d[H 2 ]/dt) diss from the absolute intensity of the continuum. The known method of determination of T vib from relative intensities of Fulcher-α bands was seriously corrected and simplified due to the revision of d → a transition probabilities and cross sections of d ← X electron impact excitation. General considerations are illustrated with examples of experiments in pure hydrogen capillary-arc and H 2 +Ar microwave discharges. In pure H 2 plasma the values of T vib obtained by two independent methods are in rather good accordance (T vib =3000-5000 K). In the H 2 +Ar microwave plasma it was observed for the first time that the shape of the continuum depends on the ratio of the mixture components. Absorption measurements of the population of the 3s 2 3p 5 4s levels of Ar together with certain computer simulations showed that the Ar*→H 2 excitation transfer plays a significant role. In our typical conditions (power flux: 4 W cm −2 , pressure p = 0.5 mbar, H 2 :Ar=1:1) the following values were obtained for the microwave discharge: (d[H 2 ]/dt) diss ≈ 2.5 − 5 · 10 17 cm −3 s −1 . The contribution of the excitation transfer is about 10-30% of the total population of the a 3 Σ + g state.

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Section: 8) So We Detected Only a Part Of The Continuum Emissionmentioning

confidence: 99%