Bulletin of the American Physical Society
42nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 56, Number 5
Monday–Friday, June 13–17, 2011; Atlanta, Georgia
Session J5: Atomic Structure and Spectroscopy |
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Chair: Greg Brown, Lawrence Livermore National Laboratory Room: A705 |
Wednesday, June 15, 2011 10:30AM - 10:42AM |
J5.00001: Magnetic-Dipole Lines in Highly-Charged Ions of Hafnium, Tantalum, and Gold J. Reader, D. Osin, J.D. Gillaspy, Yu. Ralchenko We observed spectra of highly-charged ions of Hf, Ta, and Au in the region 10-20 nm with the NIST electron beam ion trap (EBIT). Electron beam energies varied from 4.5-7.0 keV. Ionization stages were distinguished by observing intensities of the observed lines at the different beam energies. Using an extensive collisional-radiative model, we identified more than 100 new magnetic-dipole (M1) lines, mainly within the ground state configurations $3d^n $ (n=1-9) for charge states Hf$^{45+}$ to Au$^{60+}$. The results extend our recent results for M1 lines in highly ionized W [1] to these other heavy elements. The intensity ratios for some of these lines are highly sensitive to electron densities in various plasmas. We will discuss their application to density diagnostics in hot plasmas such as will be found in the ITER tokamak. \\[4pt] [1] Yu Ralchenko et al., Phys. Rev. A, submitted (2011). [Preview Abstract] |
Wednesday, June 15, 2011 10:42AM - 10:54AM |
J5.00002: ABSTRACT HAS BEEN MOVED TO M5.00006 |
Wednesday, June 15, 2011 10:54AM - 11:06AM |
J5.00003: Quantum interference and the magic angle in the observation of lithium D-lines R.C. Brown, S. Wu, J.V. Porto, C.J. Sansonetti, C.E. Simien, J.D. Gillaspy, J.N. Tan, S.M. Brewer The spectroscopy of the hyperfine components in the D-lines in atomic lithium represents a realization of the double-(or triple-) slit experiment in the frequency domain. Since the spacing between hyperfine components is less than the natural line width it is impossible to determine which component scattered a given photon. We analyze data collected from a frequency comb based precision spectroscopic measurement of the $^{6,7}$Li D-lines as a function of laser polarization [1]. Data fitted using a superposition of Voigt functions shows apparent frequency shifts which depend on the angle between the laser polarization and the direction of fluorescence collection. When restricted fluorescence collection direction and quantum interference terms are accounted for in the fitted line shape, spectra observed at all polarizations yield consistent results. At the so called ``magic angle'' of 54.7 degrees these additional quantum interference terms go to zero in analogy with the disappearance of quantum beats in the time domain.~~This may explain discrepancies between previous measurements. \\[4pt] [1] C.E.Simien et al. Can. J.Phys. \textbf{89}, 1, (2011) [Preview Abstract] |
Wednesday, June 15, 2011 11:06AM - 11:18AM |
J5.00004: ABSTRACT HAS BEEN MOVED TO U3.00009 |
Wednesday, June 15, 2011 11:18AM - 11:30AM |
J5.00005: Calibration of an Astrophysical Spectrograph with an Astro-comb in the Visible Spectral Range Chih-Hao Li, Alex Glenday, David Phillips, Sylvain Korzennik, Guoqing Noah Chang, Li-Jin Chen, Andrew Benedick, Franz Kaertner, Dimitar Sasselov, Andrew Szentgyorgyi, Ronald Walsworth Searches for extrasolar planets using the periodic Doppler shift of stellar lines are approaching Earth-like planet sensitivity. To find a 1-Earth-mass planet in an Earth-like orbit, an order of magnitude improvement in state-of-the-art radial velocity spectroscopy is necessary. An astro-comb, the combination of an ocatve-spanning laser frequency comb with a Fabry-Perot cavity, producing evenly spaced frequency markers with the potential for large wavelength coverage is a promising avenue towards improved wavelength calibration. Here we demonstrate the calibration of a high-resolution astrophysical spectrograph below the 50 cm/s level in the visible spectral range around 420 nm using an octave-spanning Ti:Sapphire laser and an ultra-low dispersion Fabry-Perot filter cavity adjusted for a mode spacing of approximately 50 GHz. Modeling of spectrograph response function and overall system stability and reproducibility will be described. [Preview Abstract] |
Wednesday, June 15, 2011 11:30AM - 11:42AM |
J5.00006: Current Status of Atomic Spectroscopy Databases at NIST Alexander Kramida, Yuri Ralchenko, Joseph Reader NIST's Atomic Spectroscopy Data Center maintains several online databases on atomic spectroscopy. These databases can be accessed via the \underline {http://physics.nist.gov/PhysRefData} web page. Our main database, Atomic Spectra Database (ASD) has recently been upgraded to v. 4.0.1. It is now fully integrated with the NIST Atomic Spectra Bibliography Databases. ASD now contains critically evaluated data for about 170,000 spectral lines and 86,000 energy levels of almost all elements in the periodic table. We continue maintaining and regularly updating our bibliography databases, ensuring comprehensive coverage of current literature on atomic spectra, including energy levels, spectral lines, transition probabilities, hyperfine structure, isotope shifts, Zeeman and Stark effects. We continue maintaining other popular databases such as the Handbook of Basic Atomic Spectroscopy Data, searchable atlases of spectra of Pt-Ne and Th-Ne lamps, and non-LTE plasma-kinetics code comparisons. [Preview Abstract] |
Wednesday, June 15, 2011 11:42AM - 11:54AM |
J5.00007: Relativistic dielectronic recombination data for low-ionized W W.R. Johnson, U.I. Safronova, A.S. Safronova We continue our work on theoretical studies of dielectronic recombination of W ions, first of highly ionized and now of low-ionized W ions. In particular, energy levels, radiative transition probabilities, and autoionization rates for [Cd]$4f^{14}5p^55l'nl$, [Cd]$4f^{14}5p^56l''nl$, [Cd]$4f^{13}5p^65l'nl$, and [Cd]$4f^{13}5p^66l''nl$ ($l'=d,f$ , $l''=s,p,d,f$, $n=5-7$ states in Pm-like tungsten (W$^{5+}$) are calculated using the relativistic many-body perturbation theory method (RMBPT code), the Multiconfiguration relativistic Hebrew University Lawrence Atomic Code (HULLAC code), and the Hartree-Fock-Relativistic method (COWAN code). Branching ratios relative to the first threshold and intensity factors are calculated for satellite lines, and dielectronic recombination (DR) rate coefficients are determined for the singly-excited [Cd]$4f^{14}5p^6nl$ ($n$=5-7). The total DR rate coefficient is derived as a function of electron temperature. These atomic data are important in modeling of N-shell radiation spectra of heavy ions generated in various collision as well as plasma experiments. The tungsten data are particulary important for fusion application. This research was sponsored by DOE under the OFES grant DE-FG02-08ER54951 and in part under the NNSA CA DE-FC52- 06NA27588. [Preview Abstract] |
Wednesday, June 15, 2011 11:54AM - 12:06PM |
J5.00008: Direct Observation of the $6S_{1/2}$ to $5D_{3/2}$ Electric Quadrupole Transition in Barium-138 Adam Kleczewski, Matt Hoffman, Eric Magnuson, Boris Blinov, Norval Fortson The $6S_{1/2}$ to $5D_{3/2}$ electric quadrupole transition at 2051 nm in Ba+ plays an important role in a number of proposed experiments.\footnote{K. Beloy, et. al. arXiv:0804.4317v1 [physics.atom-ph] 2008}$^,$\footnote{J. Sherman, et. al. arXiv:physics/0504013v2 [physics.atom-ph] 2005}$^,$\footnote{E. N. Fortson. Phys. Rev. Lett., 70(16):2383-2386, Apr 1993} We present the results of the first narrow laser spectroscopy performed on this transition. 2051 nm light is generated by a diode pumped solid state Tm,Ho:YLF laser. The laser is frequency stabilized to a high finesse cavity made from ultra-low expansion glass. In order to take advantage of higher performing optics and detectors available at shorter wavelengths, the 2051 nm light is frequency doubled using a periodically poled lithium niobate crystal inside a bow-tie enhancement cavity before being sent to the reference cavity. Using this laser system we observed Rabi oscillations on the $6S_{1/2}$ to $5D_{3/2}$ transition and demonstrated a laser-ion coherence time of 3 ms. [Preview Abstract] |
Wednesday, June 15, 2011 12:06PM - 12:18PM |
J5.00009: Measurement of the Land\'{e} g factor of the 5D$_{5/2}$ state of Ba II with a single trapped ion Nathan Kurz, Matthew Dietrich, Gang Shu, Thomas Noel, Boris Blinov We present a terrestrial measurement of the Land\'{e} g factor of the 5D$_5/2$ state of singly ionized barium. Measurements were performed on single Doppler-cooled $^{138}$Ba$^+$ ions in a linear Paul trap. A frequency-stabilized fiber laser with a nominal wavelength of 1.762 $\mu$m was scanned across the 6S$_{1/2}\leftrightarrow$5D$_{5/2}$ transition to spectroscopically resolve transitions between Zeeman sublevels of the ground and excited states. From the relative positions of the four narrow transitions observed at several different values for the applied magnetic field, we find a value of 1.2020$\pm$0.0005 for g(5D$_{5/2}$), a considerable improvement over the previously quoted value. [Preview Abstract] |
Wednesday, June 15, 2011 12:18PM - 12:30PM |
J5.00010: ABSTRACT WITHDRAWN |
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