Bulletin of the American Physical Society
50th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics APS Meeting
Volume 64, Number 4
Monday–Friday, May 27–31, 2019; Milwaukee, Wisconsin
Session D09: Spectroscopy, Lifetimes, Oscillator Strengths |
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Chair: Alexander Kramida, NIST Room: Wisconsin Center 103DE |
Tuesday, May 28, 2019 2:00PM - 2:12PM |
D09.00001: Searching for Heavy Elements in Neutron Star Merger Ejecta: High resolution UV-VIS spectroscopy of Au I, Au II, Au III S. J. Bromley, C. A. Johnson, C. E. Sosolik, P. C. Stancil, D. A. Ennis, S. D. Loch, J. P. Marler The astrophysical origin of heavy Z elements remains an open question. Spectroscopy of neutron star merger ejecta provides a new opportunity to directly probe regions where heavy elements may be forming, specifically as a result of active $r$-process nucleosynthesis. However, comparable laboratory and theoretical atomic data are not available for even low charge states of heavy Z elements. We present experimental and theoretical investigations for the electronic structure of Au I, Au II, and Au III. Using the Compact Toroidal Hybrid plasma experiment at Auburn University, neutral Au is sputtered and excited. Observed spectral lines for Au I, Au II, and Au III are reported. [Preview Abstract] |
Tuesday, May 28, 2019 2:12PM - 2:24PM |
D09.00002: CI-MBPT calculations of energies, transitions, and g factors of La II and La I Igor Savukov Lanthanide atoms and ions, including La II and La I, are important for astrophysical applications. La II and La I have large valence-core polarization correction and conventional configuration-interaction many-body perturbation theory, CI-MBPT, that includes valence-core correction in the second order is not sufficiently accurate. By introducing scaling factors for the second-order screening corrections, it is possible to improve accuracy for energies and transition probabilities. It is found that CI-MBPT with 10 such scaling factors, 7 of which can be estimated from a single-valence La III energies and the 3 remaining set to unity, or alternatively all 10 set to a single optimal value, after careful optimization, is able to reproduce La II energies and transition probabilities with quite high precision. La I energies are also well reproduced, although some La I transitions due to strong mixing are less accurate. In the talk, the La II and La I CI-MBPT calculations of energy levels, g-factors, transition probabilties and lifetimes will be presented and comparison with experiments and other theories will be given. Comparison showed that most CI-MBPT theoretical values agree well with experiments and the theory can be used to predict a large number of transitions. Such transitions can be used for applications in astrophysics and other fields. Also, the theoretical approach can be extended to other similar atoms and ions where valence-core interactions are large. [Preview Abstract] |
Tuesday, May 28, 2019 2:24PM - 2:36PM |
D09.00003: Observation of strong nonlinear interactions in parametric down conversion of x-rays into ultraviolet radiation Or Sefi, Sason Sofer, Edward Strizhevsky, Blanka Detlefs, Steve Collins, Sharon Shwartz Nonlinear interactions between x-rays and long wavelengths can be used as a powerful atomic scale probe for light-matter interactions and for physics of valence electrons. This probe can provide novel microscopic information in solids that is inaccessible by any existing method, hence to advance the understanding of many phenomena in condensed matter physics. However, thus far, reported x-ray nonlinear effects are very small and their observation required tremendous efforts. Here we report the observation of unexpected strong nonlinearities in parametric down-conversion (PDC) of x-rays to long wavelengths in gallium arsenide (GaAs) and in lithium niobate (LiNbO3) crystals, with efficiencies that are about 4 orders of magnitude stronger than the efficiencies measured in any crystals studied before. These strong nonlinearities cannot be explained by any known theory and indicate on possibilities for the development of a new spectroscopy method that is orbital and band selective. In this work we demonstrate the ability to use PDC of x-rays to investigate the spectral response of materials in a very broad range of wavelengths from the infrared regime to the soft x-ray regime. [Preview Abstract] |
Tuesday, May 28, 2019 2:36PM - 2:48PM |
D09.00004: DETERMINATION OF THE CORE POLARIZABILITY OF $^{87}$RB USING RF SPECTROSCOPY OF RYDBERG STATES Seth Berl, Charles Sackett, Thomas Gallagher The core electrons make a significant contribution to the total electric polarizability $\alpha$ of many-electron atoms like Rb. If the core contribution can be determined accurately, the remaining valence contribution to $\alpha$ provides constraints on the wave function and matrix elements of the valence electron. This can be useful for interpreting experiments such as parity violation or radiation shifts in atomic clocks. We report here on a measurement of the core polarizability based on radio-frequency spectroscopy of Rydberg states with large angular momentum. Preliminary results are 9.07 ± 0.01 a.u. for the dipole polarizability $\alpha_d$ and 18.3 ± 0.5 a.u. for the quadrupole polarizability $\alpha _q$. These preliminary results are consistent with previous measurements, and uncertainties are reduced by approximately a factor of 4. The dipole polarizability is consistent with high-precision theoretical calculations, but a large discrepancy between theory and experiment persists for the quadrupole value. [Preview Abstract] |
Tuesday, May 28, 2019 2:48PM - 3:00PM |
D09.00005: Rayleigh Scattering View of the Tune-out Wavelength: Application to the 1s2s $^3$S - 1s3p $^3$P Transition of Helium Gordon Drake, Jacob Manalo The tune-out wavelength is usually viewed a zero in the frequency-dependent polarizability [1,2]. This view is appropriate for an atom in an optical lattice that is fixed in space. However, for an atom interacting with a traveling plane wave from a laser, it is more appropriate to view the tune-out wavelength as a zero in the Rayleigh scattering cross section for coherent scattering. In lowest order, the two approaches are equivalent, but not when higher-order retardation corrections are taken into account. This paper presents a development of the theory, starting from the relativistic scattering matrix of QED to obtain a formulation of the problem in the velocity gauge [3]. Gauge invariance is discussed, and an equivalent length form is obtained for the leading retardation correction for S-states. The $xp_z$ retardation correction to the tune-out wavelength of helium near 304 nm is calculated to be $0.000\,560\,0236$ nm. \newline [1] B. M. Henson et al., Phys.\ Rev.\ Lett.\ {\bf 115}, 043004 (2015).\newline [2] Y.-H. Zhang et al., Phys.\ Rev.\ A {\bf 93}, 052516 (2016).\newline [3] G. W. F. Drake et al. Hyperfine Int.\ submitted (2019). [Preview Abstract] |
Tuesday, May 28, 2019 3:00PM - 3:12PM |
D09.00006: Spectroscopy of the $^{\mathrm{3}}$F$_{\mathrm{2}}^{\mathrm{o}}$ state of Radium Donald Booth, Tenzin Rabga, Michael Bishof, Kevin Bailey, Matthew Dietrich, John Greene, Peter Mueller, Thomas O'Connor, Tian Xia, Zheng-Tian Lu, Roy Ready, Jaideep Singh Electric dipole moment (EDM) searches on diamagnetic atoms are sensitive methods to detect CP-violation in the nucleus. $^{\mathrm{225}}$Ra, due to its octupole deformation, is a good candidate for searches for EDMs in hadrons. We cool and trap $^{\mathrm{225}}$Ra to use in EDM measurements, the sensitivity of which can be improved by capturing larger numbers of atoms. We plan to enhance our atom number by implementing a blue Zeeman slower via the $^{\mathrm{1}}$S$_{\mathrm{0}}\to ^{\mathrm{1}}$P$_{\mathrm{1}}$ transition at 483 nm, which may increase the capture efficiency of our MOT by two orders of magnitude. However, due to the substantial branching ratio from $^{\mathrm{1}}$P$_{\mathrm{1}}$ into $^{\mathrm{3}}$D$_{\mathrm{J}}$ levels, several repump lasers are needed to close the transition. Toward this goal, we present spectroscopic data of the $^{\mathrm{3}}$F$_{\mathrm{2}}^{\mathrm{o}}$ state of $^{\mathrm{226}}$Ra, which we plan to use for repumping the blue Zeeman slower. Using a novel technique, we measured the lifetime of the $^{\mathrm{3}}$F$_{\mathrm{2}}^{\mathrm{o}}$ state and the oscillator strengths of the different transitions out of the state, allowing us to determine the branching ratios out of the state. [Preview Abstract] |
Tuesday, May 28, 2019 3:12PM - 3:24PM |
D09.00007: Two-photon spectroscopy of the $2s3d~^1D_2$ level of neutral beryllium-9 Eryn Cook, Lucy Lin, Esther Kerns, Chelsea Perez, Will Williams We report on resonantly-enhanced two-photon spectroscopy in neutral beryllium-9. We monitor absorption on the $2s2p~^1P_1- 2s3d~^1D_2$ transition while probing the intermediate $2s^2~^1S_0 - 2s2p~^1P_1$ transition in co- and counter-propagating geometries. Both lasers are stabilized to an ultra-low expansion cavity using a triple-frequency-modulation offset-sideband technique to allow calibrated dual-frequency scans. The measurement offers potential improved determination of the absolute frequencies of both the $2s2p~^1P_1$ and $2s3d~^1D_2$ states. [Preview Abstract] |
Tuesday, May 28, 2019 3:24PM - 3:36PM |
D09.00008: A New Approach for Two Photon Ground State Spectroscopy of Ultracold 6Li40K molecules Yang Anbang, Sofia Botsi, Sunil Kumar, Sambit Pal, Mark Lam, Andrew Laugharn, Kai Dieckmann Ultracold bi-alkaline dipolar molecules have attracted wide attention for long lifetime and large permanent electric dipole moment, which makes them good candidates for future application in Quantum Simulation, Quantum computation and Metrology. Scientists have been trying to transfer these ultracold molecules, which are often formed by Feshbach association, to their absolute ro-vibronic ground state using Stimulated Rapid Adiabatic Passage(StiRAP). StiRAP requires a hyperfine resolved 3 level energy structure. In order to find the optimal path from ground state to excited state, one photon loss spectroscopy and 2 Photon Alter Townes Spectroscopy is often performed. In previous experiments, people were using a strongly singlet/triplet mixed excited vibrational state as a intermediate state. To find the correct path to ground state, it requires much effort to pick 1 single hyperfine state among tens of hyperfine states. In our lab, we are using a different method. Starting from a stretched Feshbach state, we pick a pure singlet state as our intermediate state for StiRAP. Using these method, we won't be confused by the hyperfine structure of one photon loss spectroscopy. This method can also be applied to other ultracold molecule group. [Preview Abstract] |
Tuesday, May 28, 2019 3:36PM - 3:48PM |
D09.00009: Fabrication, characterization, and application of short photonic microcells Sajed Hosseini-Zavareh, Ryan Luder, Kushan Weerasinghe, MANASADEVI THIRUGNANASAMBANDAM, Brian R. Washburn, Kristan L. Corwin, Cosmin Blaga We have developed short (6-10 cm) connectorized acetylene-filled photonic microcells (PMCs') from photonic bandgap fiber (PBGF) for moderate accuracy frequency measurements. There are groups and companies that use various fabrication techniques to make long, robust, and portable PMCs for various goals. Our novel fabrication technique is appropriate for short PMCs. The gas-filled all-fiber fabrication technique creates short, compact, robust, and portable cells that can be easily integrated into small lasers and optical devices for frequency calibration. The aforementioned PMC has a moderate accuracy of 10 MHz in finding the P13 line center and is designed in such a way that can be connected to photodiodes. Finally, repeatable measurements show that the PMCs are stable in terms of total pressure for a long period of time. [Preview Abstract] |
Tuesday, May 28, 2019 3:48PM - 4:00PM |
D09.00010: Identification of New Transitions in Fifth Spectrum of Cerium Abdul Wajid, S. Jabeen The spectrum of four-times ionized Cerium has been observed with 3-m normal incident vacuum spectrograph in the 300-2000 angstrom wavelength region with triggered spark source. The Ab-initio pseudo relativistic CI calculations carried out for $5p^{6}$, $5p^{5}(4f+6p)$ and $5p^{5}(5d+6s+6d)$ configurations for even and odd system respectively, with the inclusion of interacting configurations using Cowan’s code. We have re-investigated previously determined levels of the $5p^{6}$, $5p^{5}4f$, $5p^{5}5d$, $5p^{5}6s$, $5p^{5}6p$ and $5p^{5}6d$ configuration. In the present analysis, we have identified 40 transitions, which are used to establish new energy levels belonging to $5p^{5}(5f+7s+8s)$ configuration. [Preview Abstract] |
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