Bulletin of the American Physical Society
Joint Fall 2017 Meeting of the Texas Section of the APS, Texas Section of the AAPT, and Zone 13 of the Society of Physics Students
Volume 62, Number 16
Friday–Saturday, October 20–21, 2017; The University of Texas at Dallas, Richardson, Texas
Session P4: Atomic, Molecular, and Optical Physics II |
Hide Abstracts |
Chair: Kuei Sun, University of Texas at Dallas Room: DGAC 1.128 |
Saturday, October 21, 2017 3:45PM - 3:57PM |
P4.00001: Real-time detection of hazardous chemicals using Swept Wavelength Resonance Raman and Coherent Anti-Stokes Raman Spectroscopy Milan Poudel, Nagapratima Kunapareddy Real time detection of hazardous chemicals, explosives and bacteria is still a challenging problem. At Naval Research Laboratory, we have successfully detected and identified these hazardous chemicals by using Swept Wavelength Resonance Raman Detection (SWOrRD) technique, which produces 2D Resonance Raman spectra of target sample. We are currently working on next generation hazardous detection technique via Multiplex Coherent Anti Stokes Raman Spectroscopy using high rep rate (250 KHz) ytterbium laser. Preliminary results on the detection and identification of various chemicals, explosives {\&} explosive precursors will be presented. [Preview Abstract] |
Saturday, October 21, 2017 3:57PM - 4:09PM |
P4.00002: Theoretical Investigations of the Structures and the Ring-Puckering Vibrations for Several Bicyclic Molecules Esther J. Ocola, Lauren A. Wieding, Jaan Laane Ab initio calculations using the MP2/cc-pVTZ method have been carried out to calculate the structures and relative energies of the different conformations of five bicyclic molecules including bicyclo[3.1.0]hexane, 3-oxabicyclo[3.1.0]hexane, 6-oxabicyclo[3.1.0]hexane, 3,6-oxabicyclo[3.1.0]hexane, and bicyclo[3.1.0]hexan-3-one. Theoretical ring-puckering potential energy functions in terms of the ring-puckering coordinate have been calculated for each of the molecules and these were compared to those previously determined experimentally from spectroscopic data. Each potential function is asymmetric and has a single energy minimum corresponding to where the five-membered ring is puckered in the same direction as the attached three-membered ring. The calculations show that the ring-puckering motion is somewhat coupled to the ring-twisting and ring-flapping motions. Natural bond orbital analysis has also been performed and studied for these molecules and the wavefunctions for the lowest ring-puckering energy levels have been computed. [Preview Abstract] |
Saturday, October 21, 2017 4:09PM - 4:21PM |
P4.00003: $^{\mathrm{13}}$C dynamic nuclear polarization using a mixture of BDPA and trityl OX063 Christopher Parish, Peter Niedbalski, Qing Wang, Fatemeh Kashami, Lloyd Lumata Recently, there have been growing efforts to optimize dynamic nuclear polarization (DNP) in pursuit of achieving the highest enhancements of NMR spectroscopy and imaging (MRI) signals. A substantial portion of such optimization efforts has focused upon the role of free radicals in DNP. In this work, we have examined the effects of changing the concentration of a 1:1 mixture of two narrow line-width free radicals: trityl OX063 (trityl) and 1,3-bisdiphenylene-2-phenylallyl (BDPA). The polarization profiles, maxima, and build-up times were compared for different concentrations of trityl and BDPA under the constraint that both radicals had the same concentration. This study found that the polarization maxima displayed a sort of competition between two contributors to the intensity: the spin-lattice relaxation time and the number of polarizing centers. As expected based upon the mechanics of DNP, the extrapolated build-up times fell with increasing radical concentration. These results are discussed in the context of thermal mixing DNP mechanism. [Preview Abstract] |
Saturday, October 21, 2017 4:21PM - 4:33PM |
P4.00004: Visualizing Molecular Wavefunctions Using Monte Carlo Methods Steve Alexander, R.L. Coldwell Using a grid of up to 65 machines and variational Monte Carlo methods we have calculated the electron density, the intracule density, the extracule density, the electron density difference, two versions of the kinetic energy density, the Laplacian of the electron density, the Laplacian of the intracule density and the Laplacian of the extracule density of the ground state of H$_{\mathrm{2}}$, Li$_{\mathrm{2}}$, Be$_{\mathrm{2}}$, B$_{\mathrm{2}}$, C$_{\mathrm{2}}$, N$_{\mathrm{2}}$, O$_{\mathrm{2}}$ and F$_{\mathrm{2}}$ near their equilibrium distance. We discuss how contour plots of these properties can be used to visualize the distributions of electrons in each molecule. [Preview Abstract] |
Saturday, October 21, 2017 4:33PM - 4:45PM |
P4.00005: $I$-Au$_{\mathrm{60}}$: Chiral Symmetry Breaking Yields a Perfect Golden Shell of Singular Rigidity Sean Mullins, Hans-Christian Weissker, J. Jesus Pelayo, Ignacio Garzon, Robert Whetten, Xochitl Lopez-Lozano The unique properties of elemental gold (Z$=$79, Au) derive from the extreme relativistic contraction of its atomic core \textit{[Xe] }5$d^{\mathrm{10}}$ orbitals. Among these manifest properties are a propensity toward planarity, 2D bonding (\textit{5d}$_{z2}$\textit{ - 6s }hybridization) and high electro-negativity (2.54) exceeding that of any other metallic or semi-metallic element. We report an astounding consequence: a chiral symmetry-breaking, i.e. the predicted spontaneous formation of a chiral-icosahedral shell ($I$-Au$_{\mathrm{60}})$ from achiral ($I_{h})$ precursor forms, accompanied by a contraction in the Au-Au bonding and hence the radius of this \textit{perfect golden sphere}, in which all 60 atomic sites are chemically equivalent. This structure, which resembles that most complex of semi-regular (Archimedean) polyhedra (3.3.3.5*), may be viewed as an optimal topological solution to the problem: how to close a 60-vertex 2D (triangular) net in 3D. The singular rigidity of the $I$-Au$_{\mathrm{60}}$ manifests in uniquely discrete structural, vibrational, electronic, and optical signatures, which are reported as a guide to its experimental detection and ultimately its isolation in material forms. Its high (implicated) electronegativity suggests routes to obtaining it as a spherically aromatic $I$-Au$_{\mathrm{60}}(^{\mathrm{6-,12-)}}$ salts of various inert counter-cations. Its large internal void could also hold a complex as large as $I_{h}$-M$_{\mathrm{12}}$C$_{\mathrm{60}}$, M $=$ a mono- or di-valent metal ion. [Preview Abstract] |
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