Quenching of O(1S) by O(3P)

The rate constant for the quenching of O(¹S) by O(³P) has been measured in a flow system using a pulsed source of O(¹S) (1470 Å photolysis of N₂O) and NO titration of flowing N atoms as a source of O(³P). The time dependence of the emission intensity of 5577 Å from O(¹S) was measured as a function of O(³P) concentration. The rate constant derived from these data was ${\text{7.5 × 10}}^{\text{−12}}\hspace{0.17em}{\mathrm{cm}}^3\hspace{0.17em}{\sec }^{\text{−1}}$ , a value larger than had been previously estimated. In addition, an estimated upper limit of the rate constant for quenching of O(¹S) by ground state N atoms of ${\text{1× 10}}^{\text{−12}}\hspace{0.17em}{\mathrm{cm}}^3\hspace{0.17em}{\sec }^{\text{−1}}$ was obtained.