861.5 nm. Photodetachment Spectroscopy at the lowest O- ion threshold. Robert Mohr, Davidson College, Davidson, North Carolina. Abstract.
Photodetachment Spectroscopy at the lowest O- ion threshold
Robert Mohr, Davidson College, Davidson, North Carolina
Photodetachment from the negative oxygen ion in a magnetic field is a well-studied phenomenon at the transition known as the electron affinity. However, the goal of this work is to study the spectroscopy of the lowest energy detachment transition, which occurs approximately 20 meV below the electron affinity. A Penning ion trap was used to trap the ions and photodetachment was achieved using a continuous wave tunable diode laser. High-resolution spectroscopy has allowed us to resolve the energy of the lowest detachment threshold.
The electronics used to detect the image current produced by the oscillating oxygen ion cloud.
A plot showing the fraction of ions surviving detachment as a function of photon energy. The threshold transition can be observed approximately around a photon energy of 11607.75 cm-1.
A second scan showing the fraction of ions surviving detachment as a function of photon energy. The threshold transition here can be observed around a photon energy of 11607.80 cm-1.
 C. Blondel, W. Chaibi, C. Delsart, and C. Drag, J. Phys. B. 39, 1409 (2006).
 C. Blondel, C. Delsart, C. Valli, S. Yiou, M.R. Godefroid and S. Van Eck, Phys. Rev. A. 64, 052504 (2001).
 P. R. Bevington, Data Reduction and Error Analysis for the
Physical Sciences(McGraw-Hill, New York, 1969).
 W. A. M. Blumberg, “Laser Photodetachment Spectroscopy of Negative Ions in a Magnetic Field” (PhD Thesis, Harvard University, 1979).
 W. A. M. Blumberg, R. M. Jopson, and D. J. Larson, Phys. Rev. Lett. 40, 1320 (1978).
 W. A. M. Blumberg, W. M. Itano, and D. J. Larson, Phys. Rev. A. 19, 139 (1979).
 C. W. Clark, Phys. Rev. A. 28, 83 (1983).
 H. G. Dehmelt and F. L. Walls, Phys. Rev. Lett. 21, 127 (1968).
 D. J. Griffiths, Introduction to Quantum Mechanics 2nd Ed (Pearson Education, Upper Saddle River, NJ, 2005).
 C. Heinemann, W. Koch, G. G. Lindner and D. Reinen, Phys. Rev. A. 52, 1024 (1995).
 G. Herzberg, Atomic Spectra and Atomic Structure (Dover Publications, New York, 1945).
 A. K. Langworthy, D. M. Pendergrast, and J. N. Yukich, Phys. Rev. A. 69, 025401 (2004).
 D. J. Larson and R. Stoneman, J. de Physique. 43, C285 (1982).
 D. J. Larson and R. Stoneman, Phys. Rev. A. 31, 2210 (1985).
 D. M. Pendergrast and J. N. Yukich, Phys. Rev. A. 67, 062721 (2003).
 B. M. Smirnov, Physics of Atoms and Ions (Springer, New York, 2003).
 E. P. Wigner, Phys. Rev. 73, 1002 (1948).
 J. N. Yukich, “Electron Wave Packets and Ramsey Interference in a Magnetic Field” (PhD Thesis, University of Virginia, 1996).
 J. N. Yukich, C. T. Butler, and D. J. Larson, Phys. Rev. A. 55, 3303 (1997).
 J. N. Yukich, T. Kramer, and C. Bracher, Phys. Rev. A. 68, 033412 (2003).
Thanks to Dr. John Yukich and the Davidson Physics Department