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Laser Photodetachment of Negative Ions - Fundamental Research and Applications

Sammanfattning
Photodetachment studies of atomic and molecular negative ions in the gas phase are presented. Negative ions are loosely bound quantum systems whose existence is strongly dependent on the correlations between the electrons. This makes sophisticated calculations of the structure and dynamics for these systems complex and experimental data are needed for verification. Negative ions are also important in applications such as plasma etching and atmospheric studies. One of the most important applications for negative ions is as the state of matter for injection in tandem accelerators used in Accelerator Mass Spectrometry (AMS), the most sensitive method for ultra trace isotope analysis. Using negative ions in the injection stage provides isobar suppression in cases where the contaminating isobar does not form stable negative ions. Several experiments on laser interaction with a beam of mass-selected negative ions are presented. The objective for these studies can be divided into three subgroups: structure studies, dynamic studies, and proof-of-principle experiments for applications of negative ions. In the first group, the value for the electron affinity and the fine structure splitting of phosphorus is refined. The value of the electron affinity of tungsten is improved and the origin of the photodetachment signal below threshold is discussed. Resonant structure in the cross section and the electron affinity of cerium is treated. Finally, a predicted excited state in platinum is observed experimentally for the first time. The second group consists of the lifetime measurements of metastable excited states for tellurium, selenium and silicon. These measurements were made at the magnetic heavy ion storage ring CRYRING at Manne Siegbahn Laboratories in Stockholm. The third and last group are proof-of-principle experiments of isobar and neighboring isotope suppression by laser interaction. Suppression of up to four orders of magnitude is reached and the implementation into mass spectrometric systems are discussed.
Delarbeten
Paper I: The electron affinity of phosphorus Andersson P, Lindahl AO, Alfredsson C, et al. Source: JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS Volume: 40 Issue: 20 Pages: 4097-4107, 2007 ::DOI::10.1088/0953-4075/40/20/010
 
Paper II: The electron affinity of Tungsten. P Andersson, Peter Klason, A O Lindahl, C Diehl, O Forstner and D Hanstorp, In manuscript.
 
Paper III: Infrared photodetachment of Ce-: Threshold spectroscopy and resonance structure Walter CW, Gibson ND, Janczak CM, et al. Source: PHYSICAL REVIEW A Volume: 76 Issue: 5 Article Number: 052702 , 2007 ::DOI::10.1103/PhysRevA.76.052702
 
Paper IV: Observation of the S-2(1/2) metastable state in Pt- Andersson P, Lindahl AO, Hanstorp D, et al. Source: PHYSICAL REVIEW A Volume: 79 Issue: 2 Article Number: 022502 , 2009 ::DOI::10.1103/PhysRevA.79.022502
 
Paper V: Radiative lifetime of a bound excited state of Te- Ellmann A, Schef P, Lundin P, et al. Source: PHYSICAL REVIEW LETTERS Volume: 92 Issue: 25 Article Number: 253002 , 2004 ::DOI::10.1103/PhysRevLett.92.253002
 
Paper VI: Radiative lifetimes of metastable states of negative ions Andersson P, Fritioff K, Sandstrom J, et al. Source: PHYSICAL REVIEW A Volume: 73 Issue: 3 Article Number: 032705 , 2006 ::DOI::10.1103/PhysRevA.73.032705
 
Paper VII: Laser photodetachment mass spectrometry Sandstrom J, Andersson P, Fritioff K, et al. Source: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Volume: 217 Issue: 3 Pages: 513-520 , 2004 ::DOI::10.1016/j.nimb.2003.11.087
 
Paper VIII: Selective detection of C-13 by laser photodetachment mass spectrometry Andersson P, Sandstrom J, Hanstorp D, et al. Source: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS Volume: 266 Issue: 16 Pages: 3667-3673 , 2008 ::DOI::10.1016/j.nimb.2008.05.126
 
Paper IX: A lower limit for ground state photodetachment of hafnium and tungsten penta-fluorides. P Klason, P Andersson, A O Lindahl, D Hanstorp, C Diehl, K Wendt and O Forstner, In manuscript.
 
Paper X: Improved method for determination of the suppression of isobars in a gas-filled rf-quadrupole ion-guide. P Andersson, A O Lindahl, D Hanstorp, C C Havener, Yun liu and Yuan Liu. In manuscript
 
Universitet
Göteborgs universitet. Naturvetenskapliga fakulteten
Institution
Department of Physics ; Institutionen för fysik
Disputation
Fredagen den 29 maj 2009, kl 10.15, sal Euler, Matematiska vetenskaper, Chalmers
Datum för disputation
2009-05-29
E-post
pontus.andersson@physics.gu.se
URL:
http://hdl.handle.net/2077/20071
Samlingar
  • Doctoral Theses / Doktorsavhandlingar Institutionen för fysik
  • Doctoral Theses from University of Gothenburg / Doktorsavhandlingar från Göteborgs universitet
Fil(er)
Thesis frame (1.551Mb)
Spikblad (62.29Kb)
Datum
2009-05-07
Författare
Andersson, Pontus
Nyckelord
Negative Ions
Laser Spectroscopy
Photodetachment
Electron Affinity
Mass Spectrometry
Radiative Lifetime
Storage Rings
Publikationstyp
Doctoral thesis
ISBN
ISBN 978-91-628-7802-3
Språk
eng
Metadata
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