Time resolved laser induced fluorescence of the NH radical in low pressure N_2O flames

Abstract

Total removal rate constants from the NH(A(3)II(i)) electronic state have been obtained in low pressure (~14-Torr) N(2)O flames. The fluorescence decay constants and quantum yields Phi depend on the temperature and composition at each position interrogated in the flame. In similar conditions, Phi for NH(A(3)II(u)) is significantly greater than that for other radicals CH(A(2)Delta and B(2)Sigma(-)) and OH(A(2)Sigma(+)). A small decrease (~5%) in the electronic removal is observed with rotational excitation increasing from N' = 2 to 12 in the A state. Estimates of collisional quenching cross sections at flame temperatures are made for the important combustion species, H(2)O, C(3)H(8), C(2)H(4), and C(2)H(2).