ABSTRACT
The resonance ionization laser ion source (RILIS) produces beams for the majority of experiments at the ISOLDE on-line isotope separator. A substantial improvement in RILIS performance has been achieved through a series of upgrade steps: replacement of the copper vapor lasers by a Nd:YAG laser; replacement of the old homemade dye lasers by new commercial dye lasers; installation of a complementary Ti:Sapphire laser system. The combined dye and Ti:Sapphire laser system with harmonics is capable of generating beams at any wavelength in the range of 210-950 nm. In total, isotopes of 31 different elements have been selectively laser-ionized and separated at ISOLDE, including recently developed beams of samarium, praseodymium, polonium, and astatine.
ABSTRACT
Emission bands of TaO between 7000 and 28 000 cm(-1) were recorded with FTS techniques using an electrodeless 2450-MHz discharge and an on-line monitoring MES spectrometer. Transitions involving 14 electronic substates combining with the X(2)Delta ground state were analyzed. One of these states was not reported earlier. Three of these 14 states have transitions to both sublevels of the ground state, hence the ground state (a regular (2)Delta state) parameters were not only improved, but we also for the first time applied a Hund's case (a) description to it. In addition to these states, two additional states were analyzed from a previously unreported band at approximately 10 000 cm(-1); neither of these states combines with either the ground state or with the 14 excited states of this work. It was assumed that a (2)Sigma state is involved in this transition. An interesting feature in this work is a local perturbation in the P' state. The term value representation of the perturbation shows a derivativelike shape with normal (unperturbed) intensity variation around the center of the perturbation. A three-level interaction scheme was used to model this perturbation. Copyright 1999 Academic Press.
ABSTRACT
Doublet bands of NbO in the near infrared region have been observed in emission with FTS techniques using an electrodeless 2450 MHz discharge as a source. Transitions involving the vibrational levels v = 0-4 of a low-lying a2Delta state of configuration sigma2delta and four additional doublet states (c2Pi, d2Deltai, e2Phi, and f2Pii) have been recorded at high resolution. Furthermore, a 2Sigma state, assigned as b2Sigma-, has been observed through the c2Pi (v = 0) --> b2Sigma- (v = 0, 1) transitions in the 1.6 &mgr;m region. Rotational analyses of the doublet bands have been performed. Most of the excited doublet states lie only slightly above or below the well-known B4Pi state. The density of states is fairly high immediately above B4Pi, and characterizations of some of the states in this region involve difficulties. A currently unanalyzed band, centered at 11 820 cm-1, has been preliminarily attributed to the A4Pi --> X4Sigma- (0, 0) transition. Nuclear hyperfine effects are barely detectable in orbitally degenerate states of the doublet manifold at Doppler-limited resolution, while the b2Sigma- state of configuration sigmadelta2 shows partly resolved magnetic hyperfine structure (b = -0.08191 cm-1). Large-scale all-electron CI calculations have been performed on doublet and quartet manifolds of NbO up to 22 000 cm-1. The calculations have been performed in two steps. In the first step, the spin-orbit effects within electronic states were not considered. An excellent overall agreement with experimental energies was obtained, except for the d2Deltai state. In the second step, all spin-orbit interactions were included. Also these calculations resulted in a good agreement with the experimental observations. The calculations also predict three hitherto unobserved low-lying states: 4Phi at 8545 cm-1, 2Gamma at 8430 cm-1 and 2Sigma+ at 9648 cm-1. Copyright 1997 Academic Press. Copyright 1997Academic Press
