New Predissociations in GeH Affecting all theA²Δ State Levels

Lifetimes have been measured of the rotational levels N' = 2-18 of the GeH A 2 Δ- X 2 Π (0, 0) band yielding results in the range 75-85 ns. These are much shorter values than we had found earlier for the radiative lifetimes of the same system in the analogous molecules CH and SiH (≈ 500 ns) suggesting that all A -state levels in GeH are subjected to predissociations in the same way as in CH and SiH, i.e., through direct interactions with the continuum of the ground state. This conclusion is also supported by ab initio calculations which give a lower limit of 200 ns for the radiative lifetime of the GeH A state.