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Physics

Spectroscopy

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Displaying 551 - 575 of 948

Absolute pulse energy measurements of soft x-rays at the Linac Coherent Light Source

August 25, 2014
Author(s)
Uwe Arp, Alexander Sorokin, Ulf Jastrow, Pavle Jurani?, Svea Kreis, Mathias Richter, Yiping Feng, Dennis Nordlund, Kai Tiedtke, Philip Heimann, Bob Nagler, Hae Ja Lee, Stephanie Mack, Marco Cammarata, Oleg Krupin, Marc Messerschmidt, Michael Holmes , Michael Rowen, William Schlotter, Stefan Moeller, Joshua Turner
This paper reports novel measurements of x-ray optical radiation on an absolute scale from a recently developed source of radiation generated in the soft x-ray regime of a free electron laser. We give a brief description of the physics behind the

Vibronic Coupling in Asymmetric Bichromophores: Experimental Investigation of Diphenylmethane-d5

August 14, 2014
Author(s)
Nathan Pillsbury, Nathanael M. Kidwell, Benjamin Nebgen, Lyudmila V. Slipchenko, Kevin O. Douglass, John R. Cable, David F. Plusquellic
Vibrationally and rotationally resolved electronic spectra of diphenylmethane-d5 (DPM-d5) are reported in the isolated-molecule environment of a supersonic expansion. While small, the asymmetry induced by deuteration of one of the aromatic rings is

High-Speed Coherent Raman Fingerprint Imaging of Biological Tissues

July 20, 2014
Author(s)
Charles H. Camp, Young J. Lee, John M. Heddleston, Christopher M. Hartshorn, Angela R. Hight Walker, Jeremy N. Rich, Justin D. Lathia, Marcus T. Cicerone
We have developed a coherent Raman imaging platform using broadband coherent anti-Stokes Raman scattering (BCARS) that provides an unprecedented combination of speed, sensitivity, and spectral breadth. The system utilizes a unique configuration of laser

Millimeter Wave Detection via Autler-Townes Splitting in Rubidium Rydberg Atoms

July 17, 2014
Author(s)
Joshua A. Gordon, Christopher L. Holloway, Andrew Schwarzkopf, Dave Anderson, Stephanie Miller, Nithiwadee Thaicharoen, Georg Raithel
In this paper we demonstrate the detection of millimeter waves via Autler-Townes splitting in 85Rb Rydberg atoms. This method may provide an independent atomic-based SI-traceable method for measuring mm-wave electric fi elds, which addresses a gap in

Tests of Theory in Rydberg States of One-electron Ions

July 1, 2014
Author(s)
Joseph N. Tan, Peter J. Mohr
Comparison of optical frequency measurements to predictions of quantum electrodynamics (QED) for Rydberg states of one-electron ions can test theory and allow new determinations of constants of nature to be made. Simplifications in the QED theory of high

Mid-Infrared Time-Resolved Frequency Comb Spectroscopy of Transient Free Radicals

June 10, 2014
Author(s)
Adam J. Fleisher, Bryce Bjork, Thinh Q. Bui, Kevin C. Cossel, Mitchio Okumura, Jun Ye
Quantitative measurements in chemical kinetics require unambiguous determinations of reactant, intermediate, and product concentrations on time scales faster than the reaction rate. Direct absorption spectroscopy in the mid-infrared (mid-IR) can fulfill

Multiheterodyne spectroscopy with optical frequency combs generated from a continuous-wave laser

May 1, 2014
Author(s)
David A. Long, Adam J. Fleisher, Kevin O. Douglass, Stephen E. Maxwell, Katarzyna E. Bielska, Joseph T. Hodges, David F. Plusquellic
Dual-drive Mach-Zehnder modulators were utilized to produce power-leveled optical frequency combs (OFCs) from a continuous-wave laser. The resulting OFCs contained up to fifty unique frequency components and spanned more than 200 GHz. Simple changes to the

Energy Levels And Spectral Lines Of Quadruply Ionized Iron (Fe V)

April 24, 2014
Author(s)
Alexander Kramida
This compilation revises and extends the previously recommended list of energy levels of quadruply ionized iron (Fe V) and provides a comprehensive list of observed spectral lines and transition probabilities in this spectrum. The new level optimization

Measurement of the Kr XVIII 3d 2D5/2 lifetime in a Unitary Penning Trap

April 24, 2014
Author(s)
Nicholas D. Guise, Joseph Tan, Samuel Brewer, Charlotte F. Fischer, P. Jonsson
The lifetime of the 3d 2D5/2 in the fine-structure doublet of the Kr XVIII ground configuration is measured using a compact Penning trap with 2.2 cm3 of trapping volume. Kr17+ ions produced in an electron beam ion trap (EBIT) are extracted and captured in

Time-resolved surface infrared spectroscopy during atomic layer deposition of TiO2 using tetrakis(dimethylamido)titanium and water

April 23, 2014
Author(s)
Brent A. Sperling, John Hoang, William A. Kimes, James E. Maslar, Kristen L. Steffens, Nhan V. Nguyen
Atomic layer deposition of titanium dioxide using tetrakis(dimethylamido)titanium (TDMAT) and water vapor is studied by reflection-absorption infrared spectroscopy (RAIRS) with a time resolution of 120 ms. Decomposition of the adsorbed TDMAT is observed

Isolated line shapes of molecular oxygen: ab initio calculations versus measurements

April 8, 2014
Author(s)
Vincent T. Sironneau, Joseph T. Hodges, Jean M. Hartmann, Julien Lamouroux
We present comparisons between measured isolated line shapes of molecular oxygen in air and those calculated, free of any adjusted parameter, using requantized Classical Molecular Dynamics Simulations (rCMDS). This work extends a previous study made for a

N-methylmesoporphyrin IX fluorescence as a reporter of strand orientation in guanine quadruplexes

April 1, 2014
Author(s)
Navin C. Sabharwal, Victoria Savikhin, Joshua Turek-Herman, John M. Nicoludis, Veronika Szalai, Liliya Yatsunyk
Guanine quadruplexes (GQ) are four-stranded DNA structures formed by guanine-rich DNA sequences. Formation of GQs inhibits cancer cell survival, but detecting GQs in vivo has proved difficult, in part because of GQ structural diversity. Development of GQ

Quantum-noise-limited cavity ring-down spectroscopy

March 29, 2014
Author(s)
David Long, Adam Fleisher, Szymon S. Wojtewicz, Joseph Hodges
Spectroscopic techniques with ultra-high sensitivity allow for the study of a wide variety of physical and chemical phenomena, ranging from the interrogation of individual atoms1 and molecules2,3 to the quantitative extraction of ensemble properties from

Comparison of independently calculated ab-initio normal-mode displacements for the three C-H stretching vibrations of methanol along the internal rotation path

March 19, 2014
Author(s)
Li-Hong Xu, Ronald M. Lees, Jon T. Hougen, Joel M. Bowman, Xinchuan Huang, Stuart Carter
Comparison of graphical displays of normal-mode coefficients from recent quantum chemical projected-frequency calculations with analogous displays constructed after reexamination of results from more extensive higher-level calculations described earlier in

Optical self-focusing effect in coherent light scattering with condensates

March 3, 2014
Author(s)
Lu Deng, Edward W. Hagley, C.J. Zhu, G.X. Huang
We present a theoretical investigation of optical self-focusing effects in light scattering with condensates. Using long (>200 μs), red-detuned pulses we show numerically that a nonnegligible self-focusing effect is present that causes rapid optical beam
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