[Triumf-seminars] TRIUMF ISAC Seminar today at 16:00

[TRIUMF Seminars]

Date/Time: Fri 2019-04-26 at 16:00

Location:  ISAC2 conf. rm      

Speaker:   Peter Kunz - ISAC target physicist (TRIUMF)

Title:     Atom-at-a-time laser resonance ionization spectroscopy of nobelium

Abstract: Dr. Kunz will report on his experiments at GSI pursuing nobelium. 
"Optical spectroscopy of a primordial isotope has traditionally formed the basis for understanding the atomic structure of an element. Such studies have been conducted for most elements1 and theoretical modelling can be performed to high precision2,3, taking into account relativistic effects that scale approximately as the square of the atomic number. However, for the transfermium elements (those with atomic numbers greater than 100), the atomic structure is experimentally unknown. These radioactive elements are produced in nuclear fusion reactions at rates of only a few atoms per second at most and must be studied immediately following their production4, which has so far precluded their optical spectroscopy. Here we report laser resonance ionization spectroscopy of nobelium (No; atomic number 102) in single-atom-at-a-time quantities, in which we identify the ground-state transition 1S0  1P1. By combining this result with data from an observed Rydberg series, we obtain an upper limit for the ionization potential of nobelium. These accurate results from direct laser excitations of outer-shell electrons cannot be achieved using state-of-the-art relativistic many-body calculations5,6,7,8 that include quantum electrodynamic effects, owing to large uncertainties in the modelled transition energies of the complex systems under consideration. Our work opens the door to high-precision measurements of various atomic and nuclear properties of elements heavier than nobelium, and motivates future theoretical work."

the presentation is part of the Targets and Ion Sources group seminar - a general audience is welcome -

______________________________

General TRIUMF seminar information available at http://www.triumf.ca/home/upcoming-events/about-seminars-lectures