QUENCHING REACTIONS OF NF(A1 DELTA) BY CL2, CIF, BR2, ICL, IF, AND I2

The reactions of NF(a(1)DELTA) with the molecular halogens (X2) and inter-halogens (XY) have been studied in a flow reactor at 300 K. Observation of the rate of removal of NF(a) by X2 gives the total quenching rate constants, which increase in the order listed in the title, to a value of 15 x 10(-11) cm3 s-1 for I2. The primary quenching step seems to change from reactive quenching for Cl2, ClF, and Br2, probably to give NFX + X, to E to V transfer with formation of NF(X(3)SIGMA-) for IF, ICl and I2. The formation of NF(X(3)SIGMA-) was monitored by the excitation-transfer reaction with N2(A(3)SIGMA(u)+), which gives NF(b(1)SIGMA+). The chemical quenching channel was inferred from the absence of NF(X) formation. With ICl and I2 the NF(b(1)SIGMA+) concentration was enhanced for low [I2] or [ICl], even though NF(a(1)DELTA) was quenched, which suggests that I atoms are generated via utilization of 2NF(a(1)DELTA) molecules. The reaction with IF did not lead to enhancement of the [NF(b(1)SIGMA+)]. The rate constant for quenching of NF(a) by I atoms is in the range of (1-3) x 10(-11) cm3 s-1.