REDUCED ABSORPTION COEFFICIENT IN WINGS OF THE Na- D DOUBLET BROADENED BY O 2, N 2, CO 2 AND H 2O MOLECULES

Abstract

The new experimental data on the reduced absorption coefficient K(Δ σ) in far wings of the Na- D doublet broadened by O 2 and N 2 molecules are reported. These profiles were measured in the blue wing of the Na- D 2 line from about 2.5–1000 cm -1 and in the red wing of the Na- D 1 line from about 2.5–2500 cm -1 with respect to the corresponding line center. The measurements were performed by the absorption–emission method in the uniform, premixed, laminar, shielded C 2H 2/O 2 and C 2H 2/O 2/N 2 flames with sodium seed at T 1=2105 K and T 2=2135 K, respectively, and a pressure of 1 atm. The new wing profiles K j( Δσ) (j= O 2, N 2) are compared with the K j( Δσ) (j= CO 2, H 2 O) measured by the authors earlier. It is shown, that the K O2 ( Δσ), K N2 ( Δσ), K CO2 ( Δσ) and K H2 O( Δσ) profiles differ from each other by one or two orders of magnitude in the far quasi–static region (Δ σ>100 cm -1), while this difference is less than the factor 2 in the impact region (Δ σ<10 cm -1). On the basis of the obtained experimental data a set of the Lennard–Jones (6–12) interaction potentials for the Na(3 S,3 P)-M j pairs ( j= N 2, O 2, CO 2, H 2 O) was proposed.