Effect of changing reagent energy on reaction dynamics. VII. Dependence of product energy distribution on reagent rotational excitation in F + H 2( J)→ HF + H

Abstract

The infrared chemiluminescence method has been used to study the product vibrational and rotational distributions arising from the reaction F + H 2 → HF + H with an uncolliminated beam of normal hydrogen coming from an inlet at 77 K and at 290 K, and with para hydrogen at the same two inlet temperatures. The variation of the spin-isomer and temperature for the H 2 afforded a variety of reagent rotational distributions. The corresponding variation in product vibrational distribution was analyzed to yield detailed rate constants, k( v′| J), from specified states of reagent rotation, J = 0,1,2, into specified product vibrational levels, v′. The results can be summarized by saying that there is a small but significant decrease in the fraction of the total energy entering product vibration, ( f V), in going from J = 0 to J = 1, and then an increased in this fraction as J is further increased from J = 1 to J = 2. The product rotational excitation is invariant with J, within experimental error, over this range of J. These findings are discussed in terms of existing classical trajectory studies.