Inelastic collisions in molecular nitrogen at low temperature (2 < or = T < or = 50 K). - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Chemical Physics Année : 2007

Inelastic collisions in molecular nitrogen at low temperature (2 < or = T < or = 50 K).

J. P. Fonfría
  • Fonction : Auteur
A. Ramos
  • Fonction : Auteur
G. Tejeda
  • Fonction : Auteur
J. M. Fernández
  • Fonction : Auteur
S. Montero
  • Fonction : Auteur
J.-P. Fonfría
  • Fonction : Auteur

Résumé

Theory and experiment are combined in a novel approach aimed at establishing a set of two-body state-to-state rates for elementary processes ij --> lm in low temperature N(2):N(2) collisions involving the rotational states i,j,l,m. First, a set of 148 collision cross sections is calculated as a function of the collision energy at the converged close-coupled level via the MOLSCAT code, using a recent potential energy surface for N(2)-N(2). Then, the corresponding rates for the range of 2 < or = T < or = 50 K are derived from the cross sections. The link between theory and experiment, aimed at assessing the calculated rates, is a master equation which accounts for the time evolution of rotational populations in a reference volume of gas in terms of the collision rates. In the experiment, the evolution of rotational populations is measured by Raman spectroscopy in a tiny reference volume (approximately 2 x 10(-3) mm(3)) of N(2) traveling along the axis of a supersonic jet. The calculated collisional rates are assessed experimentally in the range of 4 < or = T < or = 35 K by means of the master equation, and then are scaled by averaging over a large set of experimental data. The scaled rates account accurately for the evolution of the rotational populations measured in a wide range of conditions. Accuracy of 10% is estimated for the main scaled rates.

Domaines

Biophysique

Dates et versions

hal-00908212 , version 1 (22-11-2013)

Identifiants

Citer

J. P. Fonfría, A. Ramos, Franck Thibault, G. Tejeda, J. M. Fernández, et al.. Inelastic collisions in molecular nitrogen at low temperature (2 < or = T < or = 50 K).. Journal of Chemical Physics, 2007, 127 (13), pp.134305. ⟨10.1063/1.2784255⟩. ⟨hal-00908212⟩
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