UV absorption study of the dissociation of SO₂ and SO in shock waves

Abstract

The thermal decomposition of SO, and of the primary dissociation product SO have been studied in shock waves by the uv absorption technique. The controversy about SO, dissociation data from uv absorption signals was resolved and attributed to the extensive overlap of SO, and SO uv absorption spectra. The derived rate coefficients

Measurements of High-, Room-, and Low-Temperature Photoabsorption Cross Sections of SO2 in the 2080- to 2950-Å Region, with Application to Io

“…), from 1720 to 2400Å at 213 K by Freeman et al (1984), and from 3000 to 3240Å at 210 K by McGee and Burris (1987). There are also high-temperature measurements under shock tube conditions (Hippler et al 1988, Plach andTroe 1984) which are not totally appropriate for planetary applications. We have previously reported the absolute absorption cross sections of SO 2 at 295 K over several selected wavelength regions (Wu and Judge, 1981).…”

Falloff curves of the recombination reaction O + SO + M .fwdarw. SO2 + M in a variety of bath gases

“…to react for a period of . During this time, the local concentrations reach the values cA(x,At) and cB(x,At), and the change of the concentration of both reactants is Ac(x,At) = cA(x,0) -cA(x,At) = cB(x,0) -cB(x,At) (13) which can be calculated from Ac(x,At) = cb(x,0)F/(F -1) -cB(x,0)/(F -1) (14) where cA(x,0) F = expj[cA(x,0) -cB(x,0)]fcA/j (15) cB(x,0) Equations 14 and 15 are obtained from the integrated rate equations of reaction 1. In case of complex reaction mechanisms, the system of differential rate equations must be solved numerically.10 The concentrations c¡(x,Aí) at the end of the reaction step are the initial values for the next diffusion step.…”

Experiments and Calculations on Rate Coefficients for Pyrolysis of SO2 and the Reaction O + SO at High Temperatures

“…Previous reports of smaller rate coefficients, [3][4][5] although having a similar E a , are clearly in error; the possibility that the absorption of SO interferes with that of SO 2 has been discussed previously. 6 Figure 5 shows a temporal profile of S atoms during pyrolysis of SO 2 at 3369 K; about 12% of S atoms are produced in ∼300 µs under such experimental conditions. The concentration of S atoms decreases as temperature decreases and becomes nearly undetectable ∼2258 K, as shown in trace B of Figure 6.…”