Measurement of rotational relaxation in the ground state of methane perturbed by argon at low temperature

D. V. Kalinin (1) , D. K. Bronnikov (1) , Yu. G. Selivanov (2) , Tony Gabard (3) , Jean-Paul Champion (3) , J.-C. Hilico (3)

1 NRC KI - National Research Center "Kurchatov Institute"
2 LPI RAS - P. N. Lebedev Physical Institute of the Russian Academy of Sciences [Moscow]
3 LPUB - Laboratoire de Physique de l'Université de Bourgogne

Relaxation processes at low temperature in methane perturbed by argon have been investigated on the basis of new measurements. Diode laser absorption spectra of methane in the region of the dyad nu2/nu4 in supersonic expansions have been recorded. The time of relaxation of the ground state mean rotational energy was derived from the observed dependences of the rotational temperature on the concentration in the jet. A semi-classical model was used to calculate the state-to-state relaxation rate constants at room temperature. The evaluation of the time of relaxation of the mean rotational energy using semi-empirical temperature dependence laws is presented and discussed.

D. V. Kalinin, D. K. Bronnikov, Yu. G. Selivanov, Tony Gabard, Jean-Paul Champion, et al.. Measurement of rotational relaxation in the ground state of methane perturbed by argon at low temperature. Journal of Quantitative Spectroscopy and Radiative Transfer, 1999, 62 (1), pp.13-27. ⟨10.1016/S0022-4073(97)00194-5⟩. ⟨hal-01053970⟩