Through a combination of experimental measurements, theoretical computations, and phenomenological modeling, Dr. Curtis studies the structure of highly excited and highly ionized atoms. These ions are studied experimentally using a particle accelerator to create a beam of singly ionized atoms, all moving with the same speed and direction. A very thin foil interposed in the beam path causes some atomic electrons to be stripped away and others to be excited to higher states. Because the speed of the beam is a few percent of the speed of light, the time evolution of the birth, life, and death of these ions is clearly revealed on a scale of billionths of a second by the emission of light along the flight path.
![[Photo of Beam]](beam_crop.jpg)
Photo of a 700 keV Li+ beam (speed 4.4 mm/ns) traversing
a thin (2x10-5 cm) carbon foil. Blue light near the foil
is from the Li2+ 4f-5g transitions (wavelength 4500 Å,
lifetime 3 ns, decay length 1.3 cm). Green light downstream is from the
Li+ 1s2s-1s2p transition (wavelength 5485 Å,
lifetime 44 ns, decay length 19 cm).
With this method, the high density excitation conditions produce copious single and multiple electron excitation, and the low density decay conditions provide a field-free and collision-free environment for their time-resolved study. Position sensitive detection methods are used to obtain simultaneous multiplexed measurements as functions of both the wavelength and the time after excitation. Because the atom undergoes successive decay in which each electron cascades from one orbit to another, the mathematical content of this decay process can be very complicated. To eliminate this problem, Dr. Curtis and his students have devised methods that relate the decay curves for the final and the next-to-final steps, which remove these cascade effects and permit highly precise determination of the lifetimes.
The program involves extensive national and international collaboration utilizing not only the 330 kV University of Toledo Heavy Ion Accelerator (THIA), but also accelerators at the University of Lund in Sweden, the University of Bochum in Germany, and Argonne National Laboratory. Many of the measurements have been directed toward applications in the interpretation of astrophysical data from the Hubble Space Telescope, for the diagnosis of plasma data from the Joint European Torus (JET) controlled nuclear fusion tokamak reactor in Culham, England, and in applications relevant to the development of X-ray lasers.
2013
M. Brown, R. E. Irving, S. R. Federman, S. Cheng and L. J. Curtis, "Oscillator strengths for ultraviolet transitions in P II – The multiplet at 1308 Å," Astrophys. J. (in preparation).
2012
L. J. Curtis, "Ett tjugohundratalsperspektiv som underlag för kurser i elementär fysik ," Kosmos 2012, Svenska Fysikersamfundet, Swedish Science Press, Uppsala SE, 2011.
2011
L. J. Curtis, "A 21st century perspective as a primer to introductory physics," European J. Phys. 32, 1259-74 (2011).
J. Bancroft Brown, M. S. Brown, S. Cheng, L. J. Curtis, D. G.Ellis, S. R. Federman and R. E. Irving,"Experimental and Semiempirical Branching Fractions of the 3s23p2 – 3s3p3 transition array in P II," Can. J. Phys. 89, 413-6 (2011).
2010
I. Martinson, A. N. Ryabtsev, I. Kink, R. E. Irving and L. J. Curtis, "Additions to the spectra and energy levels of ionized boron, B II - B V," in Atomic Structure and Collision Processes, Man Mohan, ed. (Narosa Pub. House, New Delhi, 2010) 81-6.
L. J. Curtis, Indrek Martinson (Obituary), Physics Today 63, 65 (September 2010).
2009
M. S. Brown, S. R. Federman, R. E. Irving, S. Chang and L. J. Curtis, "Lifetimes and Oscillator Strengths for Ultraviolet Transitions in Singly Ionized Copper," Astrophys. J. 700, 880-3 (2009).
L. J. Curtis, "Einstein's contributions to atomic physics," Comments on Atomic, Molec. & Opt. Phys., Phys. Scr. 79, 058101:1-10 (2009).
L. Curtis, Sköna Maj: An Enchanted Life, (Booksurge, Charleston SC, 2009) ISBN 1-4392-3088-9.
2008
N. Reshetnikov, L. J. Curtis, M. S. Brown & R. E. Irving, "Determination of polarizabilities and lifetimes for the Mg, Zn, Cd and Hg isoelectronic sequences," Phys. Scr. 77, 015301:1-11 (2008).
S. R. Federman, L. J. Curtis, M. Brown, S. Cheng, R. E. Irving, S. Torok & R. M. Schectman, "Oscillator strengths for ultraviolet transitions in P II and Cu II," J. Phys. Conf. Series 130, 012007:1-3 (2008).
2007
L. J. Curtis, "Determination of lifetimes and nonadiabatic correlations from measured dipole polarizabilities," J. Phys. B: At. Mol. Opt. Phys. 40, 3173-80 (2007).
L. J. Curtis, S. R. Federman, S. Torok, M. Brown, S. Cheng, R. E. Irving & R. M. Schectman, "The need for branching fraction measurements in multiply-charged ions" Comments on Atomic, Molec. & Opt. Phys., Phys. Scr. 75, C1-C7 (2007).
S. R. Federman, M. Brown, S. Torok, S. Cheng, R. E. Irving, R. M. Schectman, & L. J. Curtis, "Oscillator strengths for ultraviolet transitions in P II," Astrophys. J. 660, 919-21 (2007).
I. Martinson, A. N. Ryabtsev, I. Kink, R. E. Irving & L. J. Curtis, "Additions to the spectra and energy levels of ionized boron, B II - B V," in Current Developments in Atomic, Molec. & Opt. Phys. with Applications, Man Mohan, ed. (2007) pp.~81-6.
2006
A. J. Larkoski, D. G. Ellis & L. J. Curtis, "Numerical implementation of the Einstein-Brillouin-Keller quantization for arbitrary potentials," Am. J. Phys. 74, 572-7 (2006).
L. J. Curtis & D. G. Ellis, "Probabilities as a Bridge between Classical and Quantum Mechanical Treatments," Eur. J. Phys. 27, 485-496 (2006).
E. Träbert & L. J. Curtis, "Isoelectronic trends of line strength data in the Li and Be isoelectronic sequences," Comments on Atomic, Molec. and Opt. Phys., Phys. Scr. 74, C46-C54 (2006).
2005
L. J. Curtis, "Einstein's Contributions to Atomic Physics," Kosmos 2005 (Almquist & Wiksell, Uppsala Sweden 2005), pp. 43-63.
L. J. Curtis, "Transition Probabilities: Past and Future Measurements," Phys. Scr. T120, 9-14 (2005).
L. J. Curtis, "Precision Oscillator Strength and Lifetime Measurements," Chapter 17 in Springer Handbook of Atomic, Molec. & Opt. Phys. , ed. G.W.F. Drake (Springer-Verlag, Berlin, 2005), pp. 259-66.
L. J. Curtis & I. Martinson, "Atomic Structure," Chapter 27 in Electrostatic Accelerators, ed R. Hellborg (Springer-Verlag, 2005), pp. 560-80.
L. J. Curtis, "Professor Indrek Martinson: A Biographical Sketch," Physica Scripta T120, 5-6 (2005).
L. J. Curtis, "A Lifetime since Lysekil," Physica Scripta T120, 7 (2005).
I. Martinson & L. J. Curtis, "Janne Rydberg - His Life and Work," Nucl. Instrum. Meth. in Phys. Res. B 235, 17-22 (2005).
K. W. Kukla, A. E. Livingston, C. M. Vogel Vogt, H. G. Berry, R. W. Dunford, L. J. Curtis & S. Cheng, "Extreme-Ultraviolet Wavelength and Lifetime Measurements in Highly-Ionized Krypton," Can. J. Phys. 83, 1127-39 (2005).
2004
J. Steiner & L. J. Curtis, "Branching Fractions for the Mg-like 3s3p-3s3d and 3s3p-3p2 Transition Arrays," J. Phys. B: At. Mol. Opt. Phys. 37, 3771-6 (2004).
L. J. Curtis & D. G. Ellis, "Use of the Einstein-Brillouin-Keller Action Quantization," Am. J. Phys. 72, 1521-3 (2004).
2003
L. J. Curtis, Atomic Structure and Lifetimes: A Conceptual Approach, Cambridge University Press, ISBN 0 521 53635 9 (Hardback), ISBN 0 521 82939 9 (Paperback), 2003.
C. Jupén, B. Denne-Hinnov, I. Martinson & L. J. Curtis, "Additions to the Spectra of Highly Ionized Molybdenum, Mo XXIV-XXVIII," Physica Scripta 68, 230-2 (2003).
H. Nilsson, S. Ivarsson, H. Sabel, C. M. Sikström & L. J. Curtis, "Measurements of Transition Probabilities for Complex Atoms," Phys. Sc. T105, 61-6 (2003).