Collisional excitation rate coefficients of N2H+ by He
TLDR
Using a recoupling technique with close-coupling spin-free calculations de-excitation rate coefficients are obtained among hyperfine transitions for He colliding with N 2 H +, and a recently determined potential energy surface suitable for scattering calculations is used to investigate rate coefficients for temperatures between 5 and 50 K as mentioned in this paper.Abstract:
Using a recoupling technique with close-coupling spin-free calculations de-excitation rate coefficients are obtained among hyperfine transitions for He colliding with N 2 H + . A recently determined potential energy surface suitable for scattering calculations is used to investigate rate coefficients for temperatures between 5 and 50 K, and for the seven lowest rotational levels of N 2 H + . Fitting functions are provided for the Maxwellian averaged opacity tensors and for the rotational de-excitation collisional rate coefficients. The fitting functions for the opacity tensors can be used to calculate hyperfine (de)-excitation rate coefficients among elastic and inelastic rotational levels, and among the corresponding magnetic sublevels of the hyperfine structure. Certain dynamical approximations are investigated and found to be invalid.read more
Citations
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Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
TL;DR: In this paper, the authors present results of an extensive mapping survey of N2H+(1-0) in about 60 low mass cloud cores already mapped in the NH3(1,1) inversion transition line.
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The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
TL;DR: In this paper, the optically thin critical densities and the effective excitation densities to produce a 1 K km/s (or 0.818 Jy cm/s ) spectral line are tabulated for 12 commonly observed dense gas molecular tracers.
Journal ArticleDOI
The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers
TL;DR: In this paper, the dependence of the critical density and effective excitation density on physical assumptions (i.e., gas kinetic temperature and molecular column density) is analyzed for 12 commonly observed dense gas molecular tracers.
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BASECOL2012: A collisional database repository and web service within the Virtual Atomic and Molecular Data Centre (VAMDC)
Marie-Lise Dubernet,Millard H. Alexander,Yaye-Awa Ba,Naduvalath Balakrishnan,Christian Balança,Cecilia Ceccarelli,José Cernicharo,Fabien Daniel,Fabrice Dayou,M. Doronin,Fabien Dumouchel,Alain Faure,N. Feautrier,D. R. Flower,Alain Grosjean,Philippe Halvick,Jacek Kłos,François Lique,George C. McBane,Sarantos Marinakis,Nicolas Moreau,Robert Moszynski,David A. Neufeld,Evelyne Roueff,Peter Schilke,A. Spielfiedel,Phillip C. Stancil,Thierry Stoecklin,Jonathan Tennyson,Benhui Yang,A-M. Vasserot,Laurent Wiesenfeld +31 more
TL;DR: The BASECOL2012 database as mentioned in this paper is a repository of collisional data and a web service within the Virtual Atomic and Molecular Data Centre (VAMDC, http://www.vamdc.eu).
References
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Journal ArticleDOI
Dense Cores in Dark Clouds. XIV. N2H+ (1-0) Maps of Dense Cloud Cores
TL;DR: In this article, an extensive mapping survey of N2H+ (1-0) in about 60 low-mass cloud cores already mapped in the NH3 (1, 1) inversion transition line is presented.
Journal ArticleDOI
On the internal structure of starless cores: I. Physical conditions and the distribution of CO, CS, N2H+, and NH3 in L1498 and L1517B
TL;DR: In this article, the physical structure and chemical composition of two close-to-round starless cores in Taurus-Auriga, L1498 and L1517B, were characterized based on high angular resolution observations in at least two transitions of NH3,N 2H +,C S, C 34 S,C 18 O, and C 17 O, together with maps of the 1.2 mm continuum.
Journal ArticleDOI
Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
TL;DR: In this paper, the authors present results of an extensive mapping survey of N2H+(1-0) in about 60 low mass cloud cores already mapped in the NH3(1,1) inversion transition line.
Journal ArticleDOI
N2H+ and C18O Depletion in a Cold Dark Cloud
TL;DR: In this article, high angular resolution molecular line observations of C18O and N2H+ toward the dark globule B68 were used to derive the first evidence for the depletion of N 2H+, and by inference N 2, in a prestellar dark cloud.
Journal ArticleDOI
Radio-astronomical Spectroscopy of the Hyperfine Structure of N2H+
TL;DR: In this paper, high spectral resolution and high-sensitivity observations of the J = 1 → 0 transition of N2H+ at 93 GHz toward the quiescent low-mass cloud core L1512 in Taurus were presented.