Lifetimes of Excited Levels in Some Important Ion-molecules Part I: NH+, OH+and SH+

Brzozowski, J.; Elander, Nils; Erman, P.; Lyyra, Marjatta

doi:10.1088/0031-8949/10/5/009

Cited by 43 publications

(16 citation statements)

References 14 publications

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“…These results are intended to be included in astrophysical PDR model to account for the IR and UV radiative transfer due to the radiation flux. The radiative lifetimes obtained here, of ≈ 2500 ns, are in good agreement with the experimental results of Möhlmann et al (1978), and 2.5 times longer than the values reported by Brzozowski et al (1974) which were used by de Almeida & Singh (1981) to get semi-empirical Eisntein's coefficients.…”

Section: Discussionsupporting

confidence: 92%

“…There are two experimental studies reporting very different lifetimes for OH + (A 3 Π, v = 0). Brzozowski et al (1974) reported lifetimes for v between 850 and 1010 ns, obtained by averaging over rotational bands for particular OH Möhlmann et al (1978) reported a radiative lifetime for OH + (A 3 Π, v = 0) of 2500 ns, in very good agreement with the results of the present work, but considerably longer than that reported previously (Brzozowski et al 1974). These authors argued that this difference is originated from the effect of the pressure on the lifetimes in the case of longrange interactions present in charged gases.…”

Section: Einstein Coefficients For Ohsupporting

confidence: 91%

“…We may therefore conclude, that our results are rather reliable. It should be noted that the Einstein coefficients obtained by de Almeida & Singh (1981) are based on the experimental radiative lifetimes of Brzozowski et al (1974), and are therefore 2.5 times larger than those reported in this work. In this section, we consider the collisional excitation of OH + by He.…”

Section: Einstein Coefficients For Ohcontrasting

confidence: 60%

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OH⁺IN ASTROPHYSICAL MEDIA: STATE-TO-STATE FORMATION RATES, EINSTEIN COEFFICIENTS AND INELASTIC COLLISION RATES WITH He

Gómez-Carrasco

Godard

Lique

et al. 2014

ApJ

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The rate constants required to model the OH + observations in different regions of the interstellar medium have been determined using state of the art quantum methods. First, state-to-state rate constants for the H 2 (v = 0, J = 0, 1)+ O + ( 4 S) → H + OH + (X 3 Σ − , v ′ , N ) reaction have been obtained using a quantum wave packet method. The calculations have been compared with time-independent results to asses the accuracy of reaction probabilities at collision energies of about 1 meV. The good agreement between the simulations and the existing experimental cross sections in the 0.01−1 eV energy range shows the quality of the results. The calculated state-to-state rate constants have been fitted to an analytical form. Second, the Einstein coefficients of OH + have been obtained for all astronomically significant ro-vibrational bands involving the X 3 Σ − and/or A 3 Π electronic states. For this purpose the potential energy curves and electric dipole transition moments for seven electronic states of OH + are calculated with ab initio methods at the highest level and including spin-orbit terms, and the rovibrational levels have been calculated including the empirical spin-rotation and spin-spin terms. Third, the state-to-state rate constants for inelastic collisions between He and OH + (X 3 Σ − ) have been calculated using a time-independent close coupling method on a new potential energy surface. All these rates have been implemented in detailed chemical and radiative transfer models. Applications of these models to various astronomical sources show that inelastic collisions dominate the excitation of the rotational levels of OH + . In the models considered the excitation resulting from the chemical formation of OH + increases the line fluxes by about 10 % or less depending on the density of the gas.

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Section: Discussionsupporting

confidence: 92%

Section: Einstein Coefficients For Ohsupporting

confidence: 91%

Section: Einstein Coefficients For Ohcontrasting

confidence: 60%

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OH⁺IN ASTROPHYSICAL MEDIA: STATE-TO-STATE FORMATION RATES, EINSTEIN COEFFICIENTS AND INELASTIC COLLISION RATES WITH He

Gómez-Carrasco

Godard

Lique

et al. 2014

ApJ

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“…Finally, to calculate the correction factors for escape of emitters we applied the procedure described in reference [34], using the derived product velocities, dimensions of the observation zone and radiative lifetimes. The lifetime of ND(A) equals to 415 ns [35], for ND(c) it was measured to be 500 ns for v = 0 and about 230 ns for v = 1 [36], for ND + (B) and ND + (C) we used the values given in reference [37] for the corresponding electronic states of NH + , namely 980 ns and 400 ns, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The ND + (A-X) emission should lie on top of the ND + (B-X) spectrum, but the appearance of its Δv = 0 sequence is possibly weakened due to a large difference in equilibrium distances of the electronic states involved, Δr e . In addition, ND + * (A) has a longer lifetime (τ = 1080 ns) [37] than ND + * (B) (τ = 980 ns) and therefore a higher probability to escape from the observation zone. In the past, the ND + (A-X) transition was not observed in similar spectroscopic studies using accelerated ion beams, while the ND + (B-X) transition was relatively strong [45,53].…”

Section: Luminescence Spectramentioning

confidence: 99%

Optical emission in the dissociation of ammonia by low energy He+ ions

et al. 2017

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New bound electronic states of NH⁺

Amero

Vázquez

2004

Int J of Quantum Chemistry

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Ab initio MRD-CI electronic structure calculations were carried out on the NH ϩ cation. A basis set of DZ ϩ POL quality augmented with Rydberg and bond functions was employed, together with an extensive treatment of electron correlation. We find four new bound electronic states of NH ϩ , namely, three doublets ( 2 ⌬, 2 ⌺ ϩ , 2 ⌺ ϩ ) and one sextet ( 6 ⌸). A fifth bound electronic state, a quartet ( 4 ⌸) that was reported schematically in an early SCF study (Liu, H. P. D.; Verhaegen, G. J Chem Phys 1970, 53(2), 735), is calculated for the first time over a wide range of NOH distances. Electronic energies, potential energy curves, and spectroscopic constants are reported for these five states. Vertical and adiabatic excitation and ionization energies are reported, as well as vertical de-excitation energies for emission from the novel states to lower-lying bound states. The potential energy curve of NH 2ϩ (X 1 ⌺ ϩ ) was also calculated to aid in the discussion of a Rydberg bound state of NH ϩ . It is hoped that the information reported in this article will be helpful in guiding the experimental detection of these species.

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Lifetimes of Excited Levels in Some Important Ion-molecules Part I: NH⁺, OH⁺and SH⁺

Cited by 43 publications

References 14 publications

OH⁺IN ASTROPHYSICAL MEDIA: STATE-TO-STATE FORMATION RATES, EINSTEIN COEFFICIENTS AND INELASTIC COLLISION RATES WITH He

OH⁺IN ASTROPHYSICAL MEDIA: STATE-TO-STATE FORMATION RATES, EINSTEIN COEFFICIENTS AND INELASTIC COLLISION RATES WITH He

Optical emission in the dissociation of ammonia by low energy He+ ions

New bound electronic states of NH⁺

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Lifetimes of Excited Levels in Some Important Ion-molecules Part I: NH+, OH+and SH+

Cited by 43 publications

References 14 publications

OH+IN ASTROPHYSICAL MEDIA: STATE-TO-STATE FORMATION RATES, EINSTEIN COEFFICIENTS AND INELASTIC COLLISION RATES WITH He

OH+IN ASTROPHYSICAL MEDIA: STATE-TO-STATE FORMATION RATES, EINSTEIN COEFFICIENTS AND INELASTIC COLLISION RATES WITH He

Optical emission in the dissociation of ammonia by low energy He+ ions

New bound electronic states of NH+

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Product

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Lifetimes of Excited Levels in Some Important Ion-molecules Part I: NH⁺, OH⁺and SH⁺

OH⁺IN ASTROPHYSICAL MEDIA: STATE-TO-STATE FORMATION RATES, EINSTEIN COEFFICIENTS AND INELASTIC COLLISION RATES WITH He

OH⁺IN ASTROPHYSICAL MEDIA: STATE-TO-STATE FORMATION RATES, EINSTEIN COEFFICIENTS AND INELASTIC COLLISION RATES WITH He

New bound electronic states of NH⁺