Abstract

The rate coefficient for quenching NF(b¹∑) by F₂, IF, and I₂ has been measured from 300 to 570 K in a low pressure flow system. None has a strong temperature dependence. The temperature dependence of the rate coefficient can be fitted by k = (BT^1/2) exp(−E/RT) with B = 1.0 × 10⁻¹² cm³ s⁻¹ K⁻¹, E = 0.39 kcal mol⁻¹ for F₂, B = 3.7 × 10⁻¹² cm³ s⁻¹ K⁻¹, E = −0.16 kcal mol⁻¹ for IF, and B = 6.4 × 10⁻¹² cm³ s⁻¹ K^−1/2 and E = −0.07 kcal for I₂. This implies that the efficiency of energy transfer from NF(b) to the potential lasing species, IF, would be 7% at 800 K. The rate coefficient at 330 K is 4.4 × 10⁻¹² cm³ s⁻¹, 1.0 × 10⁻¹⁰ cm³ s⁻¹, and 1.6 × 10⁻¹⁰ cm³ s⁻¹ for F₂, IF, and I₂. NF(b) was made by reaction of argon metastables with NF₂ and its concentration measured by its emission near 528 nm. IF was produced by reaction of F with CF₃I and measured by laser-induced fluorescence (LIF) which also measured its ground state rotational distribution from which the gas temperature was determined. Because of the formation of IF_n on the tube walls at elevated temperature, LIF was used to measure [IF] and calibrated at 330 K.

© 1986 Optical Society of America