Quantum yields for the collisionally induced dissociation of excited I2B3Π0 +u to I(52P½)+ I(52P); non-equilibrium effects in the combination of atoms
Abstract
Highly vibrationally excited I2B3Π0+u was produced by irradiation of iodine vapour, through interference filters, to the long wavelength of the 4985 Å convergence limit. Relative quantum yields were measured for the endothermic dissociation, I2B3Π0+u+ M → I(52P½)+ I(52P)+ M, where M = He or Xe. Quantum yields of I(52P½) formation were indistinguishable in the two inert gases at all wavelengths. The yields of the excited atoms are surprisingly large; for example, molecules excited 3 kT below the limit undergo the endothermic dissociation with 0.5 probability.
The results are discussed in relation to fluorescence quenching measurements and non-equilibrium effects in the combination of atoms.