Determination of channel interaction in barium for five5d7dperturbers: TheD21,3F2,1P1,3S1,and3P0states

The measurement of the interaction in barium of five bound, doubly excited perturber states with singly excited Rydberg series is reported. The five perturbers are the 5d7d ${}^1$ $D_2$, 5d7d ${}^3$ $F_2$, 5d7d ${}^1$ $P_1$, 5d7d ${}^3$ $S_1$, and 5d7d ${}^3$ $P_0$ states. The J=2 perturbers interact with the 6snd ${}^3$ $D_2$ and 6snd ${}^1$ $D_2$ Rydberg series; the J=1 perturbers interact with the 6snd ${}^3$ $D_1$ and 6sns ${}^3$ $S_1$ series; and the J=0 perturber interacts with the 6sns ${}^1$ $S_0$ series. We observe the relative cross section for photoexcitation of the 6p7d autoionizing resonance from each of the perturbers and interacting states nearby in energy where the photon energy roughly corresponds to the energy separation of the 5d and 6p ${\mathrm{Ba}}^{+}$ states. The relative strength of the transition is directly related to the 5d7d character of the bound states. Good agreement with extensive previous work is obtained for the 5d7d ${}^1$ $D_2$ and 5d7d ${}^3$ $P_0$ states. General agreement with previous work is obtained for the 5d7d ${}^3$ $F_2$, 5d7d ${}^1$ $P_1$, and 5d7d ${}^3$ $S_1$ states and specific discrepancies are clarified.