Dipole moments and transition probabilities of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>a</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mi>Σ</mml:mi></mml:mrow><mml:mrow><mml:mi>g</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math>–b<mml

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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“…5 Therefore we have to analyze all available data about electron impact excitation and spontaneous decay of the upper levels.…”

Section: Constants Of Elementary Processesmentioning

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.…”

Section: Introductionmentioning

confidence: 99%

uv continuum emission and diagnostics of hydrogen-containing nonequilibrium plasmas

Lavrov

Melnikov

Käning³

et al. 1999

Phys. Rev. E

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“…The transition probability from a discrete vibrational state v to a continuum vibrational state with wavenumber k is calculated as [45][46][47]:…”

Section: Transition Presentmentioning

confidence: 99%

“…D(R) is the transition moment between the electronic states; ν vk is the frequency of the emitted light; and g is the statistical weight. Table 5 lists references for D(R) used in the present model, and ψ k (R) is calculated by applying the Numerov method [33] to Equation (7), and ψ k (R) is normalized at large R according to [46,47]. Table 5.…”

Section: Transition Presentmentioning

confidence: 99%

Rovibrationally Resolved Time-Dependent Collisional-Radiative Model of Molecular Hydrogen and Its Application to a Fusion Detached Plasma

Sawada

Goto

2016

Atoms

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Abstract:A novel rovibrationally resolved collisional-radiative model of molecular hydrogen that includes 4,133 rovibrational levels for electronic states whose united atom principal quantum number is below six is developed. The rovibrational X 1 Σ + g population distribution in a SlimCS fusion demo detached divertor plasma is investigated by solving the model time dependently with an initial 300 K Boltzmann distribution. The effective reaction rate coefficients of molecular assisted recombination and of other processes in which atomic hydrogen is produced are calculated using the obtained time-dependent population distribution.

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“…The a X i + b X: transition is also a major contributor to the opacity in stellar atmospheres [21]. The spectra resulting from electron-impact excitation of the a X i state of H2 and D2 have been measured and calculated with high accuracy [21].…”

mentioning

confidence: 99%

Fine and hyperfine structure in three low-lying³Σ⁺states of molecular hydrogen

et al. 2003

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The fine structure constant (electron spin-spin coupling) and the hyperfine structure parameters (electron-nuclear spin coupling, including spin-rotation and electron-nuclear quadrupole coupling) in the low-lying triplet states b3C:, a3C,f and e3C; of molecular hydrogen and deuterium are calculated using a recently developed technique with full configuration interaction and multiconfiguration self-consistent field wave functions. The secondorder spin-orbit coupling contribution to the 3C+ states splitting is negligible, and the calculations therefore provide a good estimate of the zero-field splitting based only on the electron spin-spin coupling values. For the bound a3C; state a negligible zero-field splitting is found, in qualitative agreement with the e-a spectrum. The zero-field splitting parameter is considerable for the repulsive b3C; state (~1 cm-') and of intermediate size for the bound e3C: state. The isotropic hyperfine coupling constant is very large not only for the valence b3C; state (1580MHz) but also for the Rydberg a and e triplet states (~1400MHz). The quadrupole coupling constants for the deuterium isotopes are negligible (0.04-0.07 MHz) for all studied triplet states. The electric dipole activity of the spin sublevels in the triplet-singlet transitions to the ground state is estimated by means of the quadratic response technique.

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Dipole moments and transition probabilities of thea3Σg+–b

Cited by 23 publications

References 14 publications

uv continuum emission and diagnostics of hydrogen-containing nonequilibrium plasmas

uv continuum emission and diagnostics of hydrogen-containing nonequilibrium plasmas

Rovibrationally Resolved Time-Dependent Collisional-Radiative Model of Molecular Hydrogen and Its Application to a Fusion Detached Plasma

Fine and hyperfine structure in three low-lying³Σ⁺states of molecular hydrogen

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Dipole moments and transition probabilities of thea3Σg+–b

Cited by 23 publications

References 14 publications

uv continuum emission and diagnostics of hydrogen-containing nonequilibrium plasmas

uv continuum emission and diagnostics of hydrogen-containing nonequilibrium plasmas

Rovibrationally Resolved Time-Dependent Collisional-Radiative Model of Molecular Hydrogen and Its Application to a Fusion Detached Plasma

Fine and hyperfine structure in three low-lying3Σ+states of molecular hydrogen

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Fine and hyperfine structure in three low-lying³Σ⁺states of molecular hydrogen