Eur. Phys. J. D (2014) 68: 71
https://doi.org/10.1140/epjd/e2014-40617-6

Regular Article

On laser spectroscopy of the element nobelium (Z = 102)

¹ Helmholtz-Institut Mainz, 55128 Mainz, Germany
² Institut für Kernphysik, Universität Mainz, 55099 Mainz, Germany
³ GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
⁴ TRIUMF, Vancouver BC, V6T 2A3, Canada
⁵ Institut für Angewandte Physik, TU-Darmstadt, 64289 Darmstadt, Germany
⁶ Fakultät für Physik, Ludwig-Maximilians-Universität München, 85748 Garching, Germany

^a e-mail: m.laatiaoui@gsi.de

Received: 8 October 2013
Received in final form: 2 February 2014
Published online: 27 March 2014

Abstract

Optical transitions were sought for in ²⁵⁴No, which was produced at the UNILAC accelerator at GSI in the reaction ²⁰⁸Pb (⁴⁸Ca, 2n)²⁵⁴No. After separation from the projectile beam by the velocity filter SHIP, the nobelium ions were stopped inside a buffer gas cell and guided onto a tantalum filament. The activation energy for desorption of nobelium from tantalum was determined to be 246   (24) kJ/mol. In a first experiment, the search for the 7s7p¹P₁ level of nobelium by laser resonance ionization spectroscopy was started. Based on level predictions by multi-configuration Dirac-Fock and relativistic coupled-cluster calculations, the wavenumber ranges from 25   900 cm^-1 to 28   260 cm^-1 and from 28   040 cm^-1 to 31   000 cm^-1 were scanned with two excimer laser-pumped dye lasers and a frequency doubled Nd:YAG laser pumped OPO system, respectively. The measurements delivered no clear evidence for a resonance. However, five wavenumber positions, viz. 27   997 cm^-1, 28   015 cm^-1, 28   230 cm^-1, 28   792 cm^-1, and 29   516 cm^-1, remain potential candidates for the transition and subject for upcoming investigations.