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 E03: Applications of Atomic, Molecular, and Collisional DataLive
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Chair: Dipti, NIST |
Tuesday, June 1, 2021 2:00PM - 2:12PM Live |
E03.00001: First-Principles Molecular Spectra of Air Mark C Zammit, Jeffery Leiding, Julie Jung, James P Colgan, Eddy M Timmermans Comprehensive and highly accurate rovibronic spectral measurements of air molecules are critical to the modeling of low-temperature plasmas and air in extreme conditions. However, with the lack of experimental data, first-principles approaches are key to generating complete molecular line lists. For the last five decades approximate approaches have been utilized to calculate comprehensive line lists of air molecules. Here we put these approximations to the test, comparing these results with our first principles state-of-the-art calculations for OH and NO, which form in significant abundance in air under extreme conditions. We will discuss the methods employed to calculate molecular rovibronic states, present emission spectra and equation of state results. By exploring the implications of emission spectra produced from approximate and state-of-the-art calculations we devise a ground-truth-oriented quantification of the line-list differences. |
Tuesday, June 1, 2021 2:12PM - 2:24PM Live |
E03.00002: Measurement of electron-impact ionization cross section of He-like Fe24+ Yang Yang, Dipti Dipti, Amy Gall, Galen O'Neil, Paul Szypryt, Adam Hosier, Nancy Brickhouse, Randall K Smith, Adam Foster, Joseph Tan, Aung S Naing, David R Schultz, Yuri Ralchenko, Endre Takacs
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Tuesday, June 1, 2021 2:24PM - 2:36PM Live |
E03.00003: Absolute nuclear radii of Ir isotopes determined by EUV spectroscopy of highly charged ions Adam T Hosier, Dipti Fnu, Roshani Silwal, Alain Lapierre, Steven A Blundell, Samuel Sanders, Yang Yang, Paul Szypryt, Joseph Tan, Aung S Naing, Joan M Dreiling, Gerald Gwinner, Antonio C Villari, Yuri Ralchenko, Endre Takacs High-statistics, precision EUV spectroscopy was implemented in measuring the nuclear radii difference between Os and Ir for determination of the absolute nuclear radius of Ir. The EBIT facility at NIST produced highly charged ions at a beam energy of about 18 keV. Flat-field grazing incidence spectrometer with a CCD pixel resolution of about 0.1 eV was used to record the Na-like 3s1/2–3p1/2 D1 line and the Mg-like and 3s2 1S0–3s3p-1P1 line of both elements. The energy shifts of the elements’ transitions were measured over several days by cycling the injection of Os, Ir, and Ne into the EBIT. The measured shifts are directly related to the mean square radii through the nuclear Seltzer moment. Calculations were performed by GRASP2K and RMBPT packages. |
Tuesday, June 1, 2021 2:36PM - 2:48PM Live |
E03.00004: Finite (6,6) Single-Walled Carbon Nanotubes with Organic Surface Defects as Candidate Single Photon Emitters Benjamin R Eller, Jacek Klos, YuHuang Wang, Charles W Clark
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Tuesday, June 1, 2021 2:48PM - 3:00PM Live |
E03.00005: Atomic Processes in Highly Ionized Xenon Plasmas Radiating Between 2.5 and 14Å Amandeep Gill, Alla S Safronova, Austin Stafford, Victor L Kantsyrev, Veronica Shlyaptseva, Ryan Childers We present a study of highly ionized xenon plasmas radiating between 2.5 and 14 Å. Comparison of x-ray line emission to non-local thermodynamic equilibrium (non-LTE) modeling provides an understanding of laboratory produced plasmas and underlying atomic processes. A new M-shell Xe non-LTE model was constructed using atomic data from the FAC to describe x-ray line emission from Xe gas-puff Z-pinch experiments. Notable results include a robust description of emission lines arising from ionization stages Zn-like to Ti-like. Expanding upon this work, we conducted a theoretical study of L-shell Xe and the effects of x-ray line polarization. In particular, we studied the polarization-dependent spectra of Na-like Xe influenced by electron beams and tested the trend towards a maximum negative polarization for large J-values. Many previous x-ray line polarization studies consider only K-shell radiation; this work focuses on L-shell radiation which is more complex to analyze due to the significant increase in number of ionization stages. Applications of this polarization work are relevant for understanding the dielectronic recombination atomic process in L-shell highly charged ions plasmas with anisotropic particle distributions such as non-thermal electron beams and for their diagnostics. |
Tuesday, June 1, 2021 3:00PM - 3:12PM Live |
E03.00006: The Opacity Project: R-Matrix Calculcations for Astrophysical Plasma Opacities Anil K Pradhan, Sultana N Nahar, Werner Eissner, Lianshui Zhao Surprisingly, solar abundances of common light elements C, N, O, Ne, etc. are uncertain by large amounts of up to ~50\%. Radiation flow in stars is governed by interior opacities of heavier elements, especially Fe. However, there are serious disagreements between current theoretical models based on the Distorted Wave approximation and experiment. We are continuing more accurate but complex Breit-Pauli R-matrix calculations for Fe ions important at the radiative and convection zones boundary, Fe~XVI-Fe~XIX. Large-scale calculations for photoionization cross sections and transition probabilities have been carried out including the heretofore neglected autoionization resonance features and plasma broadening thereof. Fe~XVII BPRM calculations include 218 coupled fine structure levels in the Fe~XVIII target wavefunction expansion, and Fe~XVIII calculations include 276 levels of Fe~XIX. It is found that huge photoexcitation-of-core (PEC) or Seaton resonances make the dominant contribution to bound-free opacity. Convergence and completeness of coupled channel wavefunction expansions and calculated opacities is also addressed. |
Tuesday, June 1, 2021 3:12PM - 3:24PM Live |
E03.00007: Interpreting the spectrum of lanthanides following thegravitational waves Sultana N Nahar In 2017, the first detection of gravitational waves due to merger of two |
Tuesday, June 1, 2021 3:24PM - 3:36PM Live |
E03.00008: Ultra-sensitive human breath analysis via cavity-enhanced frequency comb spectroscopy Qizhong Liang, Jutta Toscano, Ya-Chu Chan, P. Bryan Changala, David J Nesbitt, Jun Ye Molecules present in exhaled human breath yield a wealth of information about the physiological and metabolic status of a human body. Similar to how blood tests can be used as a disease diagnostics tool, breath analysis has attracted much attention since it enables measurements to be performed in a non-invasive and potentially real-time manner. Several molecules present in the breath have been identified as biomarkers and correlated with specific diseases, such as nitrogen monoxide with asthma, acetone with diabetes, and ammonia with renal failure. In this talk, we will report how we apply cavity-enhanced mid-infrared frequency comb spectroscopy to provide simultaneous detection of multiple breath biomarkers at exceptionally high detection sensitivity levels. |
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