INNER-SHELL AND DOUBLE-EXCITATION SPECTRUM OF RUBIDIUM INVOLVING 4P AND 5S SUBSHELLS

New high resolution observations of the 4p inner shell and of the doub ly excited states of rubidium covering the spectral region between 500 and 700 Angstrom are reported. The spectra were recorded in the first order of a 3-meter spectrograph equipped with a 5000 line/mm holograp hic grating and synchrotron radiation emitted by the 500 MeV electron accelerator as the background source of radiation. More than 130 new l evels of Rb I are reported which are interpreted as inner-shell transi tions 4p(6) 5s S-2(1/2) --> 4p(5)5s(P-3(2.1.0), P-1(1))ns, nd and the doubly excited transitions 4p(6) 5s S-2(1/2) --> 4p(5)4d(P-3(0.1.2))nl . All the observed levels lie well above the first ionization threshol d and are arranged into Rydberg series converging onto seven conspicuo us limits. The inter-channel interactions between the overlapping seri es have been parameterized using multichannel quantum defect theory.