CALCULATION OF PHOTOIONIZATION CROSS SECTIONS OF BA I

In order to explain the photoionization of artificial Ba clouds, it was necessary to calculate the corresponding cross sections from the ground state 6s2 1S0 and the metastable state 6s5d 1D2 of Ba I. They were calculated by use of the Many-Channel Quantum Method. No experimental cross sections are available, so direct comparison of the theoretical results is not possible. However, some quantities related to the 1S → 1P0 cross section have been measured and the calculated values agree well. No similar data exist for the 1D → 1P0 process. Moreover the calculations indicate that it will be difficult to measure directly this photoionization cross section due to the diffuse nature of the line in addition to the usual difficulties of populating the metastable initial state. © 1969.