Observations on O(1 D →3 P ) and O2( b 1Σ g + → X 3Σ g −) following O2 photodissociation

Time-resolved studies have been made on the energy transfer process O(1D)+O2→O(3P)+O2(b 1Σg+)v. O(1D) was generated by O2 photodissociation at ?1600 Å, using an H2 laser, and observed by its emission at 6300 Å. Only the v=0 and 1 levels are produced in O2(b1Σg+) by energy transfer, in the ratio k1/k0=0.7. The quantum efficiency of converting O(1D) electronic energy into O2(b 1Σg+) is 0.77±0.2, in agreement with the most recent determination. O2(b 1Σg+)v=1 is quenched very rapidly by O2, with a rate coefficient of 2.2×10−11 cm3 molec−1 s−1. This is almost six orders of magnitude faster than O2 quenching of O2(b 1Σg+)v=0 and accounts for the weakness of emission from the v=1 level in the terrestrial airglow.