Measured radiative lifetimes for H2 and HD in the E,F 1Σ+g electronic state

We have used tunable, pulsed ultraviolet laser radiation to prepare H2 and HD in selected rovibronic levels of the E,F 1Σ+g electronic state. This state is accessible from the ground state, X 1Σ+g , by means of two-photon excitation. Subsequent absorption of near infrared laser radiation by molecules prepared in the E,F 1Σ+g state produces ions that are detected by a time-of-flight mass spectrometer. Radiative lifetimes of individual rovibronic levels are determined by measuring the ion signal as a function of the time delay between the ultraviolet and near-infrared laser pulses. A decreasing exponential function is fit to the ion signal associated with a particular rovibrational level to obtain its liftime. Measured lifetimes are in good agreement with previously reported theoretical lifetimes and the single previous measurement.