Knowledge Bank

The CIO radical is an important intermediate species in the chlorine catalytic cycle for the destruction of stratospheric ozone. Measurement of the CIO concentration profile depends critically on an accurate knowledge of the line strength of the 1-0 vibrational-rotational transition. We have computed the potential energy function and electric dipole moment function (EDMF) for CIO $X2\Pi$ using several different techniques to include electron correlation. The EDMF is used to compute Einstein coefficients, vibrational lifetimes and dipole moments in higher vibrational levels. The band strength of the 1-0 fundamental transition is computed to be $12\pm 2cm-2atm-1$ in good agreement with three experimental values, but larger than a recent value of $5cm-2atm-1$ determined from infrared heterodyne spectroscopy. Remaining questions concerning the position of the maximum of the EDMF may be resolved through experimental measurement of dipole moments of higher vibrational levels.