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Physics

Spectroscopy

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Displaying 276 - 300 of 948

High-Q dark hyperbolic phonon-polaritons in hexagonal boron nitride nanostructures

May 18, 2020
Author(s)
Georg Ramer, Mohit Tuteja, Joseph R. Matson, Marcelo I. Davanco, Thomas G. Folland, Andrey Kretinin, Takashi Taniguchi, Kenji Watanabe, Kostya Novoselov, Joshua D. Caldwell, Andrea Centrone
The anisotropy of hexagonal boron nitride (hBN) crystals gives rise to hyperbolic phonon polaritons (HPhPs), notable for their volumetric frequency-dependent angular propagation and strong confinement. For frustum (truncated nanocone) structures, theory

Linear Polarization of Anisotropically Excited X-ray Lines from the n=2 Complex in He-like Ar16+

May 13, 2020
Author(s)
Dipti Goyal, Sean W. Buechele, Amy C. Gall, Samuel C. Sanders, Csilla I. Szabo-Foster, Roshani Silwal, Endre A. Takacs, Yuri Ralchenko
High-resolution x-ray spectra were recorded at the National Institute of Standards and Technology (NIST) electron beam ion trap (EBIT) using two Johann-type crystal spectrometers, with their dispersion planes oriented parallel and perpendicular to the beam

Enhanced magnetization in proton irradiated Mn3Si2Te6 van der Waals crystals

April 28, 2020
Author(s)
L. M. Martinez, H. Iturriaga, R. Olmos, L. Shao, Y. Liu, Thuc Mai, C. Petrovic, Angela R. Hight Walker, S. R. Singamaneni
van der Waals (vdW) engineering of magnetism is a topic of increasing research interest in the community at present. We study the magnetic properties of quasi-two-dimensional layered vdW Mn3Si2Te6 (MST) crystals upon proton irradiation as a function of

Radiation damage of liquid electrolyte during focused X-ray beam photoelectron spectroscopy

April 12, 2020
Author(s)
Christopher M. Arble, Hongxuan Gou, Evgheni Strelcov, Brian D. Hoskins, Patrick Zeller, Matteo Amati, Luca Gregoratti, Andrei A. Kolmakov
Ambient pressure X-ray photoelectron spectroscopy (APXPS) has become an effective tool to interrogate chemical states at surfaces relevant to real operational conditions. Herein we employ a graphene-capped microvolume array sample platform for scanning

Field Ion Emission in an Atom Probe Microscope Triggered by Femtosecond-Pulsed Coherent Extreme Ultraviolet Light

March 12, 2020
Author(s)
Ann C. Chiaramonti Debay, Luis Miaja Avila, Benjamin W. Caplins, Paul T. Blanchard, Norman A. Sanford, Brian Gorman, David R. Diercks
This paper reports construction of an extreme ultraviolet (EUV) radiation-triggered atom probe tomograph and describes the results from initial experiments on amorphous SiO2. Femtosecond-pulsed coherent EUV radiation of 29.6 nm wavelength (41.85 eV photon

Polarization Dependence of Charge Conduction in Conjugated Polymer Films Investigated with Time- Resolved Terahertz Spectroscopy

March 6, 2020
Author(s)
Timothy J. Magnanelli, Sebastian Engmann, Jared K. Wahlstrand, John C. Stephenson, Lee J. Richter, Edwin J. Heilweil
We interrogate polarization anisotropy associated with charge conduction in films of the block co polymer PCDTPT, consisting of alternating cyclopenta dithiophene (donor) and thiadiazolo pyridine (acceptor) units with respect to sample morphology. Film

Dielectronic resonances of LMn and LNn (? 4) series in highly-charged M-shell tungsten ions

March 4, 2020
Author(s)
Dipti Goyal, A. Borovik, Jr., R. Silwal, Joan M. Dreiling, Amy C. Gall, Endre Takacs, Yuri Ralchenko
We present accurate spectroscopic measurements and detailed theoretical analysis of inner-shell LM$n$ and LN$n$ ($n$ $\geq$ 4) dielectronic resonances (DR) in highly-charged M-shell ions of tungsten. The x-ray emission from W$^49+}$ through W$^64+}$ was

Optical evidence of the chiral magnetic anomaly in the Weyl semimetal TaAs

March 4, 2020
Author(s)
Antonio L. Levy, Andrei Sushkov, Fengguang Liu, Bing Shen, Ni Ni, Howard D. Drew, Gregory Jenkins
Chiral pumping from optical electric fields oscillating at THz frequencies is observed in the Weyl material TaAs with electric and magnetic fields aligned along both the a- and c-axes. Free carrier spectral weight enhancement is measured directly for the

Carrier mobility of silicon by sub-bandgap time-resolved terahertz spectroscopy

February 26, 2020
Author(s)
Timothy J. Magnanelli, Edwin J. Heilweil
Low density charge mobility from below bandgap, two-photon photoexcitation of bulk Silicon (Si) is interrogated using time-resolved terahertz spectroscopy (TRTS). Total charge mobility is measured as a function of excitation frequency and fluence (charge

Quasi-two-dimensional magnon identification in antiferromagnetic FePS3 via magneto-Raman spectroscopy

February 18, 2020
Author(s)
Amber D. McCreary, Jeffrey R. Simpson, Thuc T. Mai, Robert D. McMichael, Jason E. Douglas, Nicholas P. Butch, Cindi L. Dennis, Rolando Valdes Aguilar, Angela R. Hight Walker
Recently it was discovered that van der Waals-bonded magnets retain long range magnetic ordering even down to a monolayer thickness, opening many avenues in fundamental physics and potential applications of these fascinating materials. One example is FePS3

Optimum lithium loading of a liquid scintillator for neutron and neutrino detection

February 11, 2020
Author(s)
Hans Pieter Mumm, Denis E. Bergeron, Mark Tyra, Jerome LaRosa, Svetlana Nour, T.J. Langford, Dimitry A. Pushin
Neutral particle detection in high-background environments is greatly aided by the ability to easily load 6Li into liquid scintillators. We describe a readily available and inexpensive liquid scintillation cocktail stably loaded with up to 1 % Li by mass

A Predictive Control Algorithm for Time-Division-Multiplexed Readout of TES Microcalorimeters

January 28, 2020
Author(s)
Malcolm S. Durkin, Galen C. O'Neil, William B. Doriese, Johnathon D. Gard, Gene C. Hilton, Jozsef Imrek, Nathan J. Ortiz, Carl D. Reintsema, Robert W. Stevens, Daniel S. Swetz, Joel N. Ullom
Time division multiplexing (TDM) uses a digital flux-locked loop (DFLL) to linearize each first-stage SQUID amplifier. Presently, the dynamic range of our TDM systems is limited by the use of a proportional-integral controller to maintain the DFLL. In this

Excess Electrons Bound to H2S Trimer and Tetramer Clusters

January 24, 2020
Author(s)
Gaoxiang Liu, Manuel Diaz-Tinoco, Sandra M. Ciborowski, Chalynette Martinez-Martinez, Svetlana Lyspustina, Jay H. Hendricks, Vincent Ortiz, Kit H. Bowen
The hydrogen sulfide trimer and tetramer anions, (H2S)3– and (H2S)4–, were generated by Rydberg electron transfer and studied via a synergy between velocity-map imaging anion photoelectron spectroscopy and high-level quantum chemical calculations. The

Circular photogalvanic spectroscopy of Rashba splitting in 2D hybrid organic-inorganic perovskite multiple quantum wells

January 16, 2020
Author(s)
Xiaojie Liu, Ashish Chanana, Uyen Huynh, Fei Xue, Paul M. Haney, Steve Blair, Xiaomei Jiang, Valy Vardeny
The two-dimensional (2D)-phenylethyl ammonium lead iodide (2D-PEPI) is an exemplary hybrid organic-inorganic halide perovskite, possessing large spin-orbit coupling and forming multiple quantum wells (MQW). We have used helicity-dependent steady state

Valley Phenomena in the Candidate Phase Change Material WSe2(1-x)Te2x

January 15, 2020
Author(s)
Sean M. Oliver, Joshua Young, Sergiy Krylyuk, Thomas L. Reinecke, Albert Davydov, Patrick M. Vora
Alloyed transition metals dichalcogenides (TMDs) provide the unique opportunity for coupling band engineering and valleytronic phenomena in an atomically-thin platform. However, valley properties remain largely unexplored in TMD alloys. Here, we

Spectrum of Ni V in the Vacuum Ultraviolet

November 27, 2019
Author(s)
Jacob W. Ward, A J. Raassen, Alexander Kramida, Gillian Nave
This work presents 97 remeasured Fe V wavelengths (1200 Å to 1600 Å) and 123 remeasured Ni V wavelengths (1200 Å to 1400 Å) with uncertainties of approximately 2 mÅ. An additional 67 remeasured Fe V wavelengths and 72 remeasured Ni V wavelengths with

On Low-Energy Tail Distortions in the Detector Response Function of X-Ray Microcalorimeter Spectrometers

November 21, 2019
Author(s)
Galen C. O'Neil, Paul Szypryt, Endre Takacs, Joseph N. Tan, Sean W. Buechele, Aung Naing, Young I. Joe, Daniel S. Swetz, Daniel R. Schmidt, William B. Doriese, Johnathon D. Gard, Carl D. Reintsema, Joel N. Ullom, John S. Villarrubia, Yuri Ralchenko
We use narrow spectral lines from the X-ray spectra of various highly charged ions to measure low-energy tail-like deviations from a Gaussian response function in a microcalorimeter X-ray spectrometer with Au absorbers at energies from 650 to 3320 eV. We

The FeoC [4Fe4S] Cluster Is Redox-Active and Rapidly Oxygen-Sensitive

November 12, 2019
Author(s)
Aaron T. Smith, Richard O. Linkous, Nathan Max, Alexandrea E. Sestok, Veronika Szalai, Kelly N. Chacon
The acquisition of iron is essential to establishing virulence among most pathogens. Under acidic and/or anaerobic conditions, most bacteria utilize the widely-distributed ferrous iron (Fe2+) uptake (Feo) system to import metabolically-required iron. The

Contactless Resonant Cavity Dielectric Spectroscopic Studies of Recycled Office Papers

November 5, 2019
Author(s)
Mary Kombolias, Jan Obrzut, Michael T. Postek, Dianne L. Poster, Yaw S. Obeng
Current product composition and quality test methods for the paper and pulp industry are rooted in wet-bench chemistry techniques which are highly subjective. These techniques have rather limited utility and cannot be used to distinguish between virgin and
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