A $sup 3$$Sigma$$sup +$/subu/ molecules in the N$sub 2$ afterglow
Excitation of N$sub 2$ by electrons with energy below the ionization threshold produces a strong afterglow in the B $Sigma$Pi/subg/--A $sup 3$$Sigma$$sup +$/subu/ system. The precursor is identified as the A $sup 3$$Sigma$$sup +$/subu/ state in the v>6 vibrational levels. The peak electron cross section of the A $sup 3$$Sigma$$sup +$/subu/--X $sup 1$$Sigma$$sup +$/subg/ system is estimated at about three times the B $sup 3$Pi/subg/--X $sup 1$$Sigma$$sup +$/subg/ transition. Deactivation rates of the A $sup 3$$Sigma$$sup +$/subu/ v>6 levels by X $sup 1$$Sigma$$sup +$/subg/ molecules vary over the 8E-12 cm$sup 3$sec$sup -1$--5E-11 cm$sup 3$sec$sup -1$ range. There is some evidence that the higher levels may relax at rates comparable to that of electronic deactivation. Deactivation of B $sup 3$Pi/subg/ by X $sup 1$$Sigma$$sup +$/subg/ molecules has a strong dependence on the vibrational level of the B $sup 3$Pi/subg/ state. The rate coefficients for this process vary between 1E-11 cm$sup 3$sec$sup -1$ and 1E-10 cm$sup 3$sec$sup -1$, with no measureable contribution by vibrational relaxation. The results suggest that production rates of the B $sup 3$Pi/subg/ state in the Lewis--Rayleigh (L--R) afterglow are much more uniformly distributed over the vibrational levels than has been previously assumed. We also suggest it is unlikely that significant amounts of energy pass through the $sup 5$$Sigma$$sup +$/subg/ state in the L--R afterglow. About 25% of the energy of atomic nitrogen recombination enters the B $sup 3$Pi/subg/ state in the L--R afterglow, according to the present results. The factors controlling the A$sup 3$$Sigma$$sup +$/sub u/ v = 0,1 population in the L--R afterglow appear to be much less well defined than has been suggested in the previous literature. (AIP)
- Research Organization:
- Department of Physics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
- NSA Number:
- NSA-33-021203
- OSTI ID:
- 4083556
- Journal Information:
- J. Chem. Phys., v. 64, no. 2, pp. 565-580, Other Information: Orig. Receipt Date: 30-JUN-76
- Country of Publication:
- United States
- Language:
- English
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