Dissociation rate measurements in SO2 + Ar mixtures behind incident shock waves

Dissociation rates of SO₂ in SO₂ + Ar mixtures at 6%, 11%, 15% and 20% of SO₂ were measured behind incident shock waves over a temperature range 4000–6000 K at initial pressures 1.0 to 2.5 Torr. The recorded laser schlieren signals exhibited two exponentials, the faster one due to vibrational relaxation and the slower one due to dissociation. The initial dissociation rate was calculated from the value of the density gradient at the point of intersection of the two exponentials. A least-squares analysis of the experimental data yielded the following empirical relations: k_SO2Ar = 3.34 × 10¹⁵ exp(?107.6 kcal mole^?1/RT) cm³/mole s, k_SO2SO2 = 5.02 × 10¹⁴ exp(?66.6 kcal mole^?1 kcal mole^?1/RT) cm³/mole s.