The air glow reaction NO+O+(M)-> NO(2)(*)+(M) at low pressures

The pressure dependence of the air glow reaction NO + O + (M) -> NO(2)(*)+ (M) was investigated in the region of 0.1 to 50 mtorr. The results show that a radiative recombination ss well as a three-body recombination is involved in the chemiluminescence. The ratios of the two-body rate constant to the three-body rate constant were measured for several added gases. At 4450 A for must aped gases a value of about 4 was obtained for the ratio of the apparent two-body rate constant of the NO(2)(*) chemiluminescent reaction at higher pressures to the two-body rats constant at low pressures. Because of the different spectral distribution of the NO(2)(*) chemiluminescence at higher pressures compared to that at lower pressures only a rough estimate of 10(2-18) to 10(-17) cm(3) molecule(-1) set(-1) can be given for the rate constant of the radiative recombination of NO + O.