Start effect and decay dynamics of vibrationally autoionizing Rydberg states of molecular hydrogen

We have studied the Stark effect and decay dynamics on singlet Rydberg states of para-H2 which converge to the v+=1, N+=0,2 ionization thresholds. The Rydberg states were excited by using 2+1 multiphoton excitation through the E,F v=0, J=0 state. The ionization and predissociation products are separately detected by time-of-flight mass spectrometry. We obtained fully resolved Stark manifolds for principal quantum numbers n=10,11, v+=1 as a function of an applied static electric field. A perturbation calculation including rotational interaction was used to simulate the experimental results. We can observe and theoretically model field-hindered autoionization and the competition between autoionization and predissociation for individual Stark components with good agreement