The line absorption technique was applied to the kinetic study of the two metastable atomic nitrogen states N (22D) and N (22P) in a flowing afterglow system. The optical absorptions of the NI1493hyphen;Aring;lpar;2p32Dminus;3s2Prpar;and 1743hyphen;Aring;lpar;2p32Dminus;3s2Prpar;transitions were used for the quantitative measurement of N (22D) and N (22P) concentrations. Deactivation of N (2D) and N (2P) by the Pyrex tube wall was found to be very efficient, i.e., occurs at nearly every collision. The secondhyphen;order rate constants at 300deg;K for the removal of N (2D) by O2, N2O, CO2, NO, N2, Ar, and He were found to belpar;6plusmn;2rpar;times;10minus;12,thinsp;lpar;3.5plusmn;1.2rpar;times;10minus;12,thinsp;lpar;5plusmn;2rpar;times;10minus;13,thinsp;lpar;7plusmn;2.5rpar;times;10minus;11,thinsp;lpar;1.6plusmn;0.7rpar;times;10minus;14,thinsp;lpar;1plusmn;0.6rpar;times;10minus;16, andle; 1.6times;10minus;16thinsp;cm3thinsp;secminus;1, respectively. It was established that the process for the first three reactant gases results in chemical reaction rather than physical quenching.
展开▼
