Accession Number : AD0655378

Title :   KINETIC AND SPECTROSCOPIC CONSTRAINTS ON THE ORIGIN OF THE N2 AFTERGLOW,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LABS DIV

Personal Author(s) : Benson,S. W.

Report Date : APR 1967

Pagination or Media Count : 15

Abstract : The large transition probability (1/10 to 1/100) for curve crossing such as occurs in N2 predissociation N2 (3B) = N2 (5-Sigma) guarantees that the rotationally 'hot' members of the 12th vibrational level of the B state (3B(12))* will always be in 'equilibrium' with free N atoms without the intervention of a third body. A kinetic scheme is suggested for these species that includes rotational and vibrational quenching in competition with electronic quenching. Fast rotational quenching gives rise to pseudo-equilibrium population of normal 3B(12) species. The equilibrium constant for 2N = N2 (3B(12)) KB is estimated at 10 to the -1.8th power liter/mole = 10 to the -22.6 power cc/particle at 300K with a negative activation energy of -2.2 kcal/mole, in good accord with recent data. Using 100000/sec as the measured radiative lifetime of the 12-8 transition yields an absolute emission intensity for this band of 10 to the 3.2 power liter/mole-sec = 10 to the -17.6 power cc/molecule-sec, again in good accord with observation. It appears from this that the 11th, 10th, and 9th vibrational levels are populated by successive collisional deactivation of the 12th level. This collisional deactivation is in competition with electronic quenching. (Author)

Descriptors :   (*NITROGEN, *AFTERGLOWS), (*CHEMILUMINESCENCE, NITROGEN), MOLECULAR ENERGY LEVELS, ELECTRON TRANSITIONS, MOLECULAR SPECTROSCOPY, REACTION KINETICS, DISSOCIATION, CHEMICAL EQUILIBRIUM, BAND SPECTRA, QUENCHING(INHIBITION)

Subject Categories : Atmospheric Physics
      Radiation and Nuclear Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE