<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>+<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>Mutual Neutralization Cross Section Obtained with Superimp

Moseley, J. T.; Aberth, W.; Peterson, James R.

doi:10.1103/physrevlett.24.435

Cited by 112 publications

(44 citation statements)

References 19 publications

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“…Only the lowest energies below a few eV are relevant for our astrophysical applications, and here the cross sections of Moseley et al (1970) decrease with energy E roughly as E~1. However, the later experiments at higher energies clearly show that the results of Moseley et al (1970) are too large by a factor of 3. This conclusion is supported by the theoretical calculations of Fussen & Kubach (1986) with good potential energy curves.…”

Section: Appendix a Rate Coefficient For H~-h`neutralizationmentioning

confidence: 92%

Heating and Ionization ofX‐Winds

Shang

Glassgold

Shu

et al. 2002

ApJ

160

155

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In order to compare the X-wind with observations, one needs to be able to calculate its thermal and ionization properties. We formulate the physical basis for the streamline-by-streamline integration of the ionization and heat equations of the steady X-wind. In addition to the well-known processes associated with the interaction of stellar and accretion funnel hot spot radiation with the wind, we include X-ray heating and ionization, mechanical heating, and a revised calculation of ambipolar di †usion heating. The mechanical heating arises from Ñuctuations produced by star-disk interactions of the time-dependent X-wind that are carried by the wind to large distances where they are dissipated in shocks, MHD waves, and turbulent cascades. We model the time-averaged heating by the scale-free volumetric heating rate, where o and v are the local mass density and wind speed, respectively, s is the distance ! mech \ aov3s~1, from the origin, and a is a phenomenological constant. When we consider a partially revealed but active young stellar object, we Ðnd that choosing a D 10~3 in our numerical calculations produces temperatures and electron fractions that are high enough for the X-wind jet to radiate in the optical forbidden lines at the level and on the spatial scales that are observed. We also discuss a variety of applications of our thermal-chemical calculations that can lead to further observational checks of X-wind theory.

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Section: Appendix a Rate Coefficient For H~-h`neutralizationmentioning

confidence: 92%

Heating and Ionization ofX‐Winds

Shang

Glassgold

Shu

et al. 2002

ApJ

160

155

View full text Add to dashboard Cite

show abstract

“…Moseley et al (1970) are the only group to have measured reaction (5) at collision energies below 3 eV. They carried out measurements to energies as low as 0.1 eV.…”

Section: Mutual Neutralizationmentioning

confidence: 99%

Cosmological Implications of the Uncertainty in H⁻Destruction Rate Coefficients

Glover

Savin

Jappsen

2006

ApJ

121

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In primordial gas, molecular hydrogen forms primarily through associative detachment of H À and H, thereby destroying the H À . The H À anion can also be destroyed by a number of other reactions, most notably by mutual neutralization with protons. However, neither the associative detachment nor the mutual neutralization rate coefficients are well determined: both may be uncertain by as much as an order of magnitude. This introduces a corresponding uncertainty into the H 2 formation rate, which may have cosmological implications. Here we examine the effect that these uncertainties have on the formation of H 2 and the cooling of protogalactic gas in a variety of situations. We show that the effect is particularly large for protogalaxies forming in previously ionized regions, affecting our predictions of whether or not a given protogalaxy can cool and condense within a Hubble time, and altering the strength of the ultraviolet background that is required to prevent collapse.

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“…In this paper I have chosen to adopt the rate listed in Galli & Palla (1998), which is derived from the data of Moseley, Aberth, & Peterson (1970). This is a conservative choice, in that it gives the lowest value of x cr ; other possibilities include the rates of Duley & Williams (1984), Dalgarno & Lepp (1987), and Croft, Dickinson, & Gadéa (1999), with the latter being preferred by the most recent compilation (Lepp et al 2002).…”

Section: Gas-phase Formationmentioning

confidence: 99%

“…These limiting cases provide useful insight into the physics of gas-phase H 2 formation, but in general we must use the full form of equation (7), which we can rewrite as Moseley et al 1970;(6) Schneider et al 1994. recombination,…”

Section: Gas-phase Formationmentioning

confidence: 99%

Comparing Gas‐Phase and Grain‐catalyzed H₂Formation

Glover

2003

ApJ

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Because H 2 formation on dust-grain surfaces completely dominates gas-phase H 2 formation in local molecular clouds, it is often assumed that gas-phase formation is never important. In fact, it is the dominant mechanism in a number of cases. In this paper, I briefly summarize the chemistry of gas-phase H 2 formation and show that it dominates for dust-to-gas ratios less than a critical value D cr . I also show that D cr is simple to calculate for any given astrophysical situation and illustrate this with a number of examples, ranging from H 2 formation in warm atomic gas in the Milky Way to the formation of protogalaxies at high redshift.

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H++H−Mutual Neutralization Cross Section Obtained with Superimp

Cited by 112 publications

References 19 publications

Heating and Ionization ofX‐Winds

Heating and Ionization ofX‐Winds

Cosmological Implications of the Uncertainty in H⁻Destruction Rate Coefficients

Comparing Gas‐Phase and Grain‐catalyzed H₂Formation

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H++H−Mutual Neutralization Cross Section Obtained with Superimp

Cited by 112 publications

References 19 publications

Heating and Ionization ofX‐Winds

Heating and Ionization ofX‐Winds

Cosmological Implications of the Uncertainty in H−Destruction Rate Coefficients

Comparing Gas‐Phase and Grain‐catalyzed H2Formation

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Product

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Cosmological Implications of the Uncertainty in H⁻Destruction Rate Coefficients

Comparing Gas‐Phase and Grain‐catalyzed H₂Formation