The excited levels argon (Ar
*;1 s
5, 1 s
4, 1 s
3 and 1 s
2) are populated by means of a DC discharge in argon-nitrogen mixtures. The densities of Ar
* (
nj;
j=5, 4, 3, 2) are measured by optical absorption techniques.The deactivation cross-sections (
Qjo) of Ar
* (1s
j) by N
2 are determined from the dependence of
nj on nitrogen fraction and are 0.75±0.10, 2.2±1.1, 0.32± 0.06 and <3.3 Å
2 for the 1 s
5, 1 s
4, 1 s
3 and 1 s
2 levels respectively.
The (0, 2) band of N
2 second positive system is observed at the same time and it is clarified that Ar
* excites the N
2 (C
3IIu), υ'=0 level which is characteristic of the nonequilibrium rotational populations such as the enhanced structure and alternating population.The ratios of the excitation rates of the N
2 (C
3IIu), υ'=0 level by electrons and Ar
* are obtained from analysis of the nonequilibrium rotational populations for different nitrogen fractions, and explained by considering
nj and
Qjo.The cross-section of rotational relaxation (30±10 Å
2) is also obtained from study of the dependence of alternating populations upon the pressure.
The collisional mechanisms between Ar
* and N
2 are discussed mainly on the basis of the one-step mechanism consisted of the ArN
2* complex proposed by Setser and Stedman.
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