ARAS MEASUREMENTS ON THE S((1)D) FORMATION IN SHOCK-HEATED COS AR MIXTURES/

The formation of electronically excited S(1D) atoms was studied during the thermal decomposition of carbonyl sulfide behind reflected shock waves by using atomic resonance absorption spectroscopy (ARAS). The ex periments were performed in highly diluted mixtures of Ar with relativ e concentrations of COS between 8 to 100 ppm in the temperature range 2130 K less-than-or-equal-to T less-than-or-equal-to 3020 K at pressur es of about 1.2 bar. The measured rate of the linear S(1D) increases d ivided by the initial reactants was found to obey the Arrhenius law: [ GRAPHICS] Assuming a fast thermalisation between the (P-3) and (1D) st ates of S atoms this result is in agreement with previous measurements of the S(P-3) formation during the thermal decomposition of COS repor ted recently [1].