H atom collisions (trac #371)

reported by: @CloudyLex

we use Drawin approximation criticized by this paper

On inelastic hydrogen atom collisions in stellar atmospheres 
Barklem, P. S., Belyaev, A. K., Guitou, M., Feautrier, N., Gadéa, F. X., & Spielfiedel, A.
2011, Astronomy and Astrophysics, 530, A94

ABSTRACT: The influence of inelastic hydrogen atom collisions on non-LTE spectral 
line formation has been, and remains to be, a significant source of uncertainty for 
stellar abundance analyses, due to the difficulty in obtaining accurate data for low-
energy atomic collisions either experimentally or theoretically. For lack of a better 
alternative, the classical "Drawin formula" is often used. Over recent decades, our 
understanding of these collisions has improved markedly, predominantly through a 
number of detailed quantum mechanical calculations. In this paper, the Drawin 
formula is compared with the quantum mechanical calculations both in terms of the 
underlying physics and the resulting rate coefficients. It is shown that the Drawin 
formula does not contain the essential physics behind direct excitation by H atom 
collisions, the important physical mechanism being quantum mechanical in 
character. Quantitatively, the Drawin formula compares poorly with the results of the 
available quantum mechanical calculations, usually significantly overestimating the 
collision rates by amounts that vary markedly between transitions.

KEYWORDS: atomic data, line: formation, stars: abundances, stars: atmospheres

REMOTE URL : http://dx.doi.org/10.1051/0004-6361/201116745
REMOTE URL : http://arxiv.org/abs/1104.1334
REMOTE URL : http://adsabs.harvard.edu/abs/2011A%26A...530A..94B
ADS URL : http://adsabs.harvard.edu/abs/2011A%26A...530A..94B
…………………………………………………………………………………

Migrated from https://www.nublado.org/ticket/371

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    "status": "new",
    "changetime": "2019-02-04T13:02:49Z",
    "_ts": "1549285369825011",
    "description": "we use Drawin approximation criticized by this paper\n\n{{{\nOn inelastic hydrogen atom collisions in stellar atmospheres \nBarklem, P. S., Belyaev, A. K., Guitou, M., Feautrier, N., Gad\u00e9a, F. X., & Spielfiedel, A.\n2011, Astronomy and Astrophysics, 530, A94\n\nABSTRACT: The influence of inelastic hydrogen atom collisions on non-LTE spectral \nline formation has been, and remains to be, a significant source of uncertainty for \nstellar abundance analyses, due to the difficulty in obtaining accurate data for low-\nenergy atomic collisions either experimentally or theoretically. For lack of a better \nalternative, the classical \"Drawin formula\" is often used. Over recent decades, our \nunderstanding of these collisions has improved markedly, predominantly through a \nnumber of detailed quantum mechanical calculations. In this paper, the Drawin \nformula is compared with the quantum mechanical calculations both in terms of the \nunderlying physics and the resulting rate coefficients. It is shown that the Drawin \nformula does not contain the essential physics behind direct excitation by H atom \ncollisions, the important physical mechanism being quantum mechanical in \ncharacter. Quantitatively, the Drawin formula compares poorly with the results of the \navailable quantum mechanical calculations, usually significantly overestimating the \ncollision rates by amounts that vary markedly between transitions.\n\nKEYWORDS: atomic data, line: formation, stars: abundances, stars: atmospheres\n\nREMOTE URL : http://dx.doi.org/10.1051/0004-6361/201116745\nREMOTE URL : http://arxiv.org/abs/1104.1334\nREMOTE URL : http://adsabs.harvard.edu/abs/2011A%26A...530A..94B\nADS URL : http://adsabs.harvard.edu/abs/2011A%26A...530A..94B\n\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026\n}}}",
    "reporter": "gary",
    "cc": "",
    "resolution": "",
    "time": "2016-09-26T22:19:56Z",
    "component": "atomic/molecular data base",
    "summary": "H atom collisions",
    "priority": "good to do",
    "keywords": "",
    "version": "trunk",
    "milestone": "no milestone",
    "owner": "nobody",
    "type": "enhancement"
}

cloudy-astrophysics / bug-tracker-migration-test

H atom collisions (trac #371) #373