Bulletin of the American Physical Society
52nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 66, Number 6
Monday–Friday, May 31–June 4 2021; Virtual; Time Zone: Central Daylight Time, USA
Session U06: Spectroscopy, Lifetimes, Oscillator StrengthsLive
|
Hide Abstracts |
Chair: Charles Sukenik, Old Dominion |
Thursday, June 3, 2021 2:00PM - 2:12PM Live |
U06.00001: AMO Physics in a Beaker Changling Zhao, Ashley Shin, Claire Dickerson, Yi Shen, Timothy Atallah, Paula Diaconescu, Anastassia Alexandrova, Justin R Caram, Wes Campbell The fundamental sensitivity limit of a vapor cell magnetometer is set by the number of spins participating in the measurement, but there is a cap to the number density that gas phase systems can reach before spin-exchange collisions and radiation trapping become a problem. As an extrapolation of high density buffer gas, liquid systems can potentially take advantage of the extremely high number density of spins achievable in solution. Here we present a Yb3+ based molecule ((thiolfan)YbCl)) that has a well-protected optical transition in the SWIR even when dissolved in solutions at room temperature. We characterize the magnetic sensitivity of the transition via Zeeman splitting, demonstrating the potential application of dissolved (thiolfan)YbCl for magnetic sensing. We also report our current progress on optically preparing and reading out ground state coherence in this liquid molecular system. |
Thursday, June 3, 2021 2:12PM - 2:24PM Live |
U06.00002: Hyperfine structure of molecular hydrogen Hubert Jozwiak, Hubert Cybulski, Piotr Wcisło Accurate experimental studies of rovibrational transitions in the ground electronic state of molecular hydrogen isotopologues provide a stringent test of quantum electrodynamics for molecules and can be used to put constraints on hypothetical beyond-Standard-Model interactions. As the accuracy of both theoretical and experimental data surpasses the MHz level, the influence of the underlying hyperfine structure, originating from the interactions involving the nuclear spin or electric quadrupole moment of the deuteron, is necessary to consider in the experimental analysis. |
Thursday, June 3, 2021 2:24PM - 2:36PM Live |
U06.00003: On-the-fly ab initio semiclassical evaluation of vibronic spectra at finite temperature [1] Tomislav Begusic, Jiri J Vanicek To compute and analyze vibrationally resolved electronic spectra at zero temperature, we have recently implemented the on-the-fly ab initio extended thawed Gaussian approximation [A. Patoz et al., J. Phys. Chem. Lett. 9, 2367 (2018)], which accounts for anharmonicity, mode–mode coupling, and Herzberg–Teller effects. Here, we generalize this method in order to evaluate spectra at non-zero temperature. In line with thermo-field dynamics, we transform the von Neumann evolution of the coherence component of the density matrix to the Schrödinger evolution of a wavefunction in an augmented space with twice as many degrees of freedom. Due to the efficiency of the extended thawed Gaussian approximation, this increase in the number of coordinates results in nearly no additional computational cost. More specifically, compared to the original, zero-temperature approach, the finite-temperature method requires no additional ab initio electronic structure calculations. At the same time, the new approach allows for a clear distinction among finite-temperature, anharmonicity, and Herzberg–Teller effects on spectra. We show, on a model Morse system, the advantages of the finite-temperature thawed Gaussian approximation over the commonly used global harmonic methods and apply it to evaluate the symmetry-forbidden absorption spectrum of benzene, where all of the aforementioned effects contribute. |
Thursday, June 3, 2021 2:36PM - 2:48PM Live |
U06.00004: Update of atomic data for the first three spectra of actinium Alexander Kramida The last comprehensive experimental study of actinium spectra (Ac I-III) was made by Meggers et al. (1957) [1]. This was a result of a comprehensive study that took several years of work and produced many tens of high resolution spectrograms recorded on photographic plates archived at the National Institute of Standards and Technology (NIST). Since then, only a few fragmentary observations were made using laser spectroscopy methods. Atomic theory also made very little progress in interpretation of these spectra. These new developments have recently been consolidated in the new actinium datasets of the NIST Atomic Spectroscopy Database (ASD). This presentation will summarize the findings that went into this update. One of them is an exceptionally good quality of the old measurements and analysis of Meggers et al. (1957). |
Thursday, June 3, 2021 2:48PM - 3:00PM Live |
U06.00005: Two-photon decay rates in heliumlike ions: finite nuclear mass effects Aaron T Bondy, Gordon W F Drake, Donald Morton Spontaneous two-photon decay rates for the 1s2s 1S0 – 1s2 1S0 transition in helium and its isoelectronic sequence up to Z = 10 are calculated, including the effects of finite nuclear mass. We use correlated variational wave functions in Hylleraas coordinates and pseudostate summations for intermediate states. The accuracy of previous work is improved by several orders of magnitude. Length and velocity gauge calculations agree to eight or more figures, demonstrating that the theoretical formulation correctly takes into account the three effects of (1) mass scaling, (2) mass polarization, and (3) radiation due to motion of the nucleus in the center-of-mass frame [1]. Algebraic relationships are derived and tested relating the expansion coefficients in powers of µ/M, where µ/M is the ratio of the electron reduced mass to the nuclear mass. Astrophysical applications of two-photon transitions to the continuum emission around 400 µm in planetary nebulae will be briefly discussed. [1] A. T. Bondy, D. C. Morton, and G.W.F. Drake, Phys. Rev. A 102, 052807 (2020). |
Thursday, June 3, 2021 3:00PM - 3:12PM Live |
U06.00006: Observation of the narrow inner-shell orbital transition in atomic erbium at 1299nm Alexander Patscheider Ultra-narrow atomic transitions have been extensively used for high-precision measurements and for the manipulation of quantum systems. |
Thursday, June 3, 2021 3:12PM - 3:24PM Live |
U06.00007: Spectroscopy of thulium atoms trapped in solid argon and neon Vinod Gaire, Chandra Raman, Colin V Parker We present a detailed study of excitation-emission spectroscopy for the magnetic dipole transitionbetween the ground state fine levels in thulium atoms trapped in crystals of argon and neon at cryogenic temperatures. We observed narrow transitions near 1140 nm when excited with visible light and also observe visible fluorescence when directly excited with infrared light. In the presence of an external magnetic field, the lines are split into multiple components. We excited the sample with circularly polarized light and preliminary results suggest the right and left polarized light have different effect in the fluorescence signal at those transitions. We will discuss efforts to identify the observed transitions with theoretical models of crystal-field-split levels. |
Thursday, June 3, 2021 3:24PM - 3:36PM Live |
U06.00008: A regular 1D system displaying signatures of quantum chaos Ahmed A Elkamshishy Resonances in particle transmission through a 1D finite lattice are studied in the presence of a finite number of impurities. Although this is a one-dimensional system that is classically integrable and has no chaos, the statistical properties of the spectrum such as the level spacing distribution and the spectral rigidity are shown to be affected by the disorder in the lattice. Transmission resonance positions are calculated using both the Wigner-Smith time-delay and a Siegert state method, which are consistent. The level statistics of the resonances is found to fit different classless of the Brody distributions. The degree of level repulsion is found to correlate with a dimensionless parameter that measures the state localization. Despite the fact that this system is classically regular, GOE and GUE level statistics are seen to emerge for specific values of the localization length. |
Thursday, June 3, 2021 3:36PM - 3:48PM Live |
U06.00009: Metastable Krypton Production with a Commercial Lamp and a Low Power Diode Laser Joshua Frechem, Grady White, Lindsay Thornton, Will D Williams, Charles I Sukenik We report progress on our investigation of all optical production of metastable-state krypton (Kr*) in a two-step excitation process (124nm +819nm) that uses a commercial Kr lamp and a low power diode laser. While metastable-state noble gases find application in a wide range of scientific experiments and applications, our primary motivation is to replace the radio-frequency discharge typically used for Kr* production in Atom Trap Trace Analysis (ATTA), a radiokrypton dating technique, thereby reducing the potential for sample contamination of the apparatus. Previous demonstration of all optical Kr* production in other groups has deployed homebuilt lamps and a Ti:S laser. Here we characterize the efficiency of a commercial lamp and replace the expensive Ti:S laser with a semiconductor diode laser. The latter is enabled by placing the excitation region in a power build-up cavity that is locked to the 819nm laser. We have investigated Kr* production in a gas cell as a function of gas pressure and 819nm laser power. Future studies are planned for all-optical Kr* production in an atomic beam. We thank Z.-T. Lu for collaborative discussions at the beginning of this project and Argonne National Lab for support. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700