Rotational excitation of HC3N by H2 and He at low temperatures

被引：0
|
作者：
Wernli, M. [1 ]
Wiesenfeld, L. [1 ]
Faure, A. [1 ]
Valiron, P. [1 ]
机构：
[1] Laboratoire d'Astrophysique, Observatoire de Grenoble, Université Joseph-Fourier, Boîte Postale 53, 38041 Grenoble Cedex 09, France
来源：
Astronomy and Astrophysics | 2007年 / 464卷 / 03期
关键词：
Aims. Rates for rotational excitation of HC3N by collisions with He atoms and H2 molecules are computed for kinetic temperatures in the range 5-20 K and 5-100 K; respectively. Methods. These rates are obtained from extensive quantum and quasi-classical calculations using new accurate potential energy surfaces (PES). The HC3N-He PES is in excellent agreement with the recent literature. The HC3N-H2 angular dependence is approximated using 5 independent H2 orientations. An accurate angular expansion of both PES suitable for low energy scattering is achieved despite the severe steric hindrance effects by the HC3N rod. Results. The rod-like symmetry of the PES strongly favours even ΔJ transfers and efficiently drives large ΔJ transfers. Despite the large dipole moment of HC3N; rates involving ortho-H2 are very similar to those involving para-H2; because of the predominance of the geometry effects. Except for the even ΔJ propensity rule; quasi classical calculations are in excellent agreement with close coupling quantum calculations. As a first application; we present a simple steady-state population model that shows population inversions for the lowest HC3N levels at H2 densities in the range 104-106 cm-3. Conclusions. The HC3N molecule is large enough to present an original collisional behaviour where steric hindrance effects hide the details of the interaction. This finding; combined with the fair accuracy of quasi classical rate calculations; is promising in view of collisional studies of larger molecules. © ESO 2007;
D O I：
暂无
中图分类号：
学科分类号：
摘要：
Journal article (JA)
引用
收藏
页码：1147 / 1154
相关论文
共 50 条
  • [1] Rotational excitation of HC3N by H2 and He at low temperatures (vol 464, pg 1147, 2007)
    Wernli, M.
    Wiesenfeld, L.
    Faure, A.
    Valiron, P.
    [J]. ASTRONOMY & ASTROPHYSICS, 2007, 475 (01) : 391 - 391
  • [2] Collisional excitation of HC3N by para- and ortho-H2
    Faure, Alexandre
    Lique, Francois
    Wiesenfeld, Laurent
    [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2016, 460 (02) : 2103 - 2109
  • [3] The rotational excitation of OCS by He at low temperatures
    Flower, DR
    [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2001, 328 (01) : 147 - 149
  • [4] N2H+ and HC3N observations of the Orion A cloud
    Tatematsu, Ken'ichi
    Kandori, Ryo
    Umemoto, Tomofumi
    Sekimoto, Yutaro
    [J]. PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 2008, 60 (03) : 407 - 419
  • [5] Effect of rotational excitation of H2 on isotopic exchange reaction with OD− at low temperatures
    [J]. Roučka, S. (stepan.roucka@mff.cuni.cz), 1600, EDP Sciences (615):
  • [6] The rotational excitation of H2 by H2
    Flower, DR
    [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1998, 297 (01) : 334 - 336
  • [7] Effect of rotational excitation of H2 on isotopic exchange reaction with OD- at low temperatures
    Roucka, S.
    Rednyk, S.
    Kovalenko, A.
    Tran, T. D.
    Plasil, R.
    Kalosi, A.
    Dohnal, P.
    Gerlich, D.
    Glosik, J.
    [J]. ASTRONOMY & ASTROPHYSICS, 2018, 615
  • [8] A survey of HC3N in extragalactic sources Is HC3N a tracer of activity in ULIRGs?
    Lindberg, J. E.
    Aalto, S.
    Costagliola, F.
    Perez-Beaupuits, J. -P.
    Monje, R.
    Muller, S.
    [J]. ASTRONOMY & ASTROPHYSICS, 2011, 527
  • [9] IMAGES OF LOW EXCITATION HC3N EMISSION FROM IRC+10-DEGREES-216
    WOOTTEN, A
    NGUYENQRIEU
    TRUONGBACH
    [J]. ASTRONOMY & ASTROPHYSICS, 1994, 290 (01) : 198 - 206
  • [10] NEW FAR INFRARED MEASUREMENTS OF THE ROTATIONAL SPECTRUM OF CYANOACETYLENE HC3N
    CHEN, W
    BOCQUET, R
    WLODARCZAK, G
    BOUCHER, D
    [J]. INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES, 1991, 12 (09): : 987 - 995
12345