AUTOIONIZATION OF LOW-LYING 5DNG STATES IN BARIUM

The autoionizing 5dng J = 1-5 states in barium for n=5-8 were investigated in a two-step pulsed laser atomic beam experiment. The wavefunctions of the 5dng configuration can be well described in a (jl)K-coupled basis. Each 5d(j)ng[K] fine structure state autoionizes into a single 6sepsilonl continuum channel. Autoionization rates, deduced from observed linewidths, are found to be symmetrically lower than values calculated using a single configuration approximation. The fine structure dependence of the autoionization rates, however, can be reproduced in these calculations.