ELECTRON-AFFINITY OF PA BY 7P ATTACHMENT AND HYPERFINE-STRUCTURE CONSTANTS FOR PA-

Valence shell relativistic configuration interaction calculations for the 7p attachment to the Pa I ground state yield one bound state, viz. , Pa- 5f(2)6d7s(2)7p J=6, with electron affinity of 0.222 eV. We found no other J's for this configuration to be bound, nor are an of the Pa - 5f(2)6d(2)7s(2) levels expected to be bound. The hyperfine structure constants for the Pa-231(-) bound state are A = 741.3 MHz and B = 130 9 MHz. Although the core-valence correlation effects are absent the ag reement between the theory (4736 cm(-1)) and experiment (4121 cm(-1)) for the position of the first excited state of Pa is good (15%). We re view our previous studies for the np attachment in rare earths to syst ematically analyze the binding of np(1/2) and np(3/2) electrons, in th ese species.