The radiative lifetime of metastable CO (aΠ3, v=)

Abstract

We present a combined experimental and theoretical study on the radiative lifetime of CO in the a Π 1 , 2 3 , v = 0 state. CO molecules in a beam are prepared in selected rotational levels of this metastable state, Stark-decelerated, and electrostatically trapped. From the phosphorescence decay in the trap, the radiative lifetime is measured to be 2.63 ± 0.03 ms for the a Π 1 3 , v = 0 , J = 1 level. From the spin-orbit coupling between the a Π 3 and the A Π 1 states a 20% longer radiative lifetime of 3.16 ms is calculated for this level. It is concluded that coupling to other Π 1 states contributes to the observed phosphorescence rate of metastable CO.