Thermal rate constants over thirty orders of magnitude for the I+H2 reaction

I-atom atomic resonance absorption spectrometry has been used to measure thermal rate constants for the I+H2 → HI+H reaction between 1755 and 2605 K in reflected shock waves. Measured rate constants can then be expressed by k1=(3.92±1.15)×10−9 exp(−21 398±658 K/T) cm3 molecule−1 s−1. Combining these results with earlier values, the rate behavior over the combined temperature range, 230 K⩽T⩽2605 K, is: k1=(4.52±0.34)×10−10 exp(−17 070±34 K/T) cm3 molecule−1 s−1. This result holds over ∼30 orders of magnitude and is discussed in terms of bimolecular rate theory.