State-specific dissociation in O2-O2 collisions by quasiclassical trajectory method

State-specific dissociation rate coefficients of oxygen in collisions with another oxygen molecule are obtained using the quasiclassical trajectory method on a six-dimensional potential energy surface at high temperatures characteristic of hypersonic flows. The present results indicate that O2-O2 rate coefficients can not be obtained by a simple scaling of a simpler O2-O dataset. A difference is observed between the present rate coefficients and those obtained via the preferential dissociation and forced harmonic oscillator models. Depletion via an exchange mechanism significantly contributes to the total dissociation rate at low temperatures and at low vibrational energies. The new set of rate coefficients is used in a one-dimensional shock flow simulation. The computed vibrational temperature is then compared to data obtained by absorption spectroscopy in the Schumann-Runge bands. A better agreement with the experimental data is achieved at moderate levels of nonequilibrium when the new dataset is implemented.