INFRARED CHEMI-LUMINESCENCE STUDIES OF THE H+CLF REACTION - ENERGY DISPOSAL AND BRANCHING RATIOS

Infrared chemiluminescence under arrested relaxation conditions has been used to study the HF and HCl formation channels of the H + ClF reaction at 300 K. From the relative infrared emission intensities the ratio of channels was determined as 4.4 in favor of HCl, the less exoergic channel. The energy disposal is 〉fV〈HCl = 0.42, 〉fR〈HCl = 0.14, 〉fT〈HCI = 0.44, and 〉fV〈HF = 0.57, rang;fR〈HF = 0.10, 〉fT〈HF = 0.33. The rotational distribution for the HF channel is much broader than for the HCl channel, which is a consequence of two pathways for HF formation. The low J component is attributed to direct reaction and the high J component to migratory collisions in which the H that intially attacked the Cl end of the molecule migrates and forms HF. Since ∼57% of the HF distribution can be assigned to a high J component, only about one-half of the HF is formed directly. The migratory aspect of the H + ClF reaction is less important than for the H + ICl or BrCl reactions recently studied by Polanyi and co-workers. The energy disposal and inferred reaction dynamics for H + ClF are compared to that for H + Cl2 and H + F2 reactions. Using a numerical procedure, improved HCl and HF transition probabilities were calculated and these values were used to convert the HCl and HF rotational line intensities to relative populations. These new HCl and HF Einstein coefficients are presented in the Appendix. © 1979 American Chemical Society.