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Your search keyword '"Emmons, Erik D."' showing total 47 results
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47 results on '"Emmons, Erik D."'

1. Waveguide-enhanced Raman spectroscopy of trace vapors with fiber-attached photonic integrated circuits

Author

Tyndall, Nathan F., primary, Emmons, Erik D., additional, Pruessner, Marcel W., additional, Butt, Jordan N., additional, Walsh, Kyle J., additional, Hung, Kevin C., additional, Roese, Erik S., additional, Wilcox, Phillip G., additional, Guicheteau, Jason A., additional, Miller, Benjamin L., additional, McGill, R. Andrew, additional, and Stievater, Todd H., additional

Published
2024
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2. Fourth-order perturbative extension of the singles-doubles coupled-cluster method

Author

Derevianko, Andrei and Emmons, Erik D.

Subjects
Physics - Atomic Physics
Abstract

Fourth-order many-body corrections to matrix elements for atoms with one valence electron are derived. The obtained diagrams are classified using coupled-cluster-inspired separation into contributions from n-particle excitations from the lowest-order wavefunction. The complete set of fourth-order diagrams involves only connected single, double, and triple excitations and disconnected quadruple excitations. Approximately half of the fourth-order diagrams are not accounted for by the popular coupled-cluster method truncated at single and double excitations (CCSD). Explicit formulae are tabulated for the entire set of fourth-order diagrams missed by the CCSD method and its linearized version, i.e. contributions from connected triple and disconnected quadruple excitations. A partial summation scheme of the derived fourth-order contributions to all orders of perturbation theory is proposed., Comment: 12 pages, 6 figures

Published
2002
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4. Supplemental Material - Quantitative Raman Cross-Sections and Band Assignments for Fentanyl and Fentanyl Analogs

Author

Wilcox, Phillip G., Emmons, Erik D., Pardoe, Ian J., Kline, Neal D., and Guicheteau, Jason A.

Subjects
FOS: Other engineering and technologies, 99999 Engineering not elsewhere classified
Abstract

Supplemental Material for Quantitative Raman Cross-Sections and Band Assignments for Fentanyl and Fentanyl Analogs by Phillip G. Wilcox, Erik D. Emmons, Ian J. Pardoe, Neal D. Kline, and Jason A. Guicheteau in Applied Spectroscopy

Published
2023
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6. Bioaerosol analysis with Raman chemical imaging microspectroscopy

Author

Tripathi, Ashish, Jabbour, Rabih E., Guicheteau, Jason A., Christesen, Steven D., Emge, Darren K., Fountain, Augustus W., Bottiner, Jerold R., Emmons, Erik D., and Snyder, A. Peter

Subjects
Microspectroscopy -- Methods, Raman spectroscopy -- Methods, Aerosols -- Identification and classification, Aerosols -- Measurement, Chemistry
Abstract

Raman chemical imaging microspectroscopy is evaluated as a technology for waterborne pathogen and bioaerosol detection. Raman imaging produces a three-dimensional data cube consisting of a Raman spectrum at every pixel in a microscope field of view. Binary and ternary mixtures including combinations of polystyrene beads, Grampositive Bacillus anthraeis, B. thudngiensis, and B. atrophaeus spores, and B. cereus vegetative cells were investigated by Raman imaging for differentiation and characterization purposes. Bacillus spore aerosol sizes were varied to provide visual proof for corroboration of spectral assignments. Conventional applications of Raman imaging consist of differentiating relatively broad areas of a sample in a microscope field of view. The spectral angle mapping data analysis algorithm was used to compare a library spectrum with experimental spectra from pixels in the microscope field of view. This direct one-to-one matching is straightforward, does not require a training set, is independent of absolute spectral intensity, and only requires univariate statistics. Raman imaging is expanded in its capabilities to differentiate and distinguish between discrete 1-6 [micro]m size bacterial species in single particles, clusters of mixed species, and bioaerosols with interference background particles.

Published
2009

8. Backscatter WERS for trace chemical analyte detection using a handheld spectrometer

Author

Tyndall, Nathan F., primary, Kozak, Dmitry A., additional, Pruessner, Marcel W., additional, McGill, R. Andrew, additional, Roberts, Courtney A., additional, Stievater, Todd H., additional, Miller, Benjamin L., additional, Luta, Ethan P., additional, Yates, Matthew Z., additional, Emmons, Erik D., additional, Wilcox, Phil G., additional, and Guicheteau, Jason A., additional

Published
2020
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15. High-pressure Raman spectroscopy of tris(hydroxymethyl)aminomethane

Author

Emmons, Erik D., Fallas, Juan C., Kamisetty, Vamsi K., Wen-Ming Chien, Covington, Aaron M., Chellappa, Raja S., Gramsch, Stephen A., Hemley, Russell J., and Chandra, Dhanesh

Subjects
High pressure chemistry -- Analysis, Methane -- Chemical properties, Methane -- Thermal properties, Transition temperature -- Evaluation, Raman spectroscopy -- Usage, Chemicals, plastics and rubber industries
Published
2010

24. Ultraviolet Surface-Enhanced Rama Scattering for Detection Applications

Author

ARMY EDGEWOOD CHEMICAL BIOLOGICAL CENTER APG MD, Emmons, Erik D, Guicheteau, Jason A, Fountain, III, Augustus W, ARMY EDGEWOOD CHEMICAL BIOLOGICAL CENTER APG MD, Emmons, Erik D, Guicheteau, Jason A, and Fountain, III, Augustus W

Abstract

Surface-enhanced resonance Raman scattering with UV excitation has the potential advantage of combining surface and molecular-resonance enhancements for a wide variety of analytes of interest. Nanostructured surfaces of Pd and Pt were formed by electroless deposition on germanium substrates. Ultrathin layers of Al were made by coating thick layers of Al on a microscope slide and partially dissolving them with hydrochloric acid. The substrates were assessed for their ability to enhance the Raman cross sections under UV excitation., The original document contains color images. This work was performed while Erik D. Emmons held a National Research Council Research Associateship Award at U.S. Army Edgewood Chemical Biological Center.

Published
2012

28. Characterization of Polymorphic States in Energetic Samples of 1,3,5-Trinitro-1,3,5-Triazine (RDX) Fabricated Using Drop-on-Demand Inkjet Technology

Author

Emmons, Erik D., primary, Farrell, Mikella E., additional, Holthoff, Ellen L., additional, Tripathi, Ashish, additional, Green, Norman, additional, Moon, Raphael P., additional, Guicheteau, Jason A., additional, Christesen, Steven D., additional, Pellegrino, Paul M., additional, and Fountain, Augustus W., additional

Published
2012
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30. Standard method for characterizing SERS substrates

Author

Guicheteau, Jason A., primary, Hankus, Mikella E., additional, Christesen, Steven D., additional, Fountain, Augustus W., additional, Pellegrino, Paul M., additional, Emmons, Erik D., additional, Tripathi, Ashish, additional, Wilcox, Phillip, additional, and Emge, Darren, additional

Published
2012
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39. New insights into multielectron processes in slow collisions of highly charged ions with many-electron neutral targets.

Author

Ali, Rami, Hasan, Ahmad A., Emmons, Erik D., and Hinojosa, Guillermo

Subjects
ELECTRONS, COLLISION spectroscopy, IONIZATION (Atomic physics)
Abstract

Recent results from triple-coincidence measurements of Auger electrons, scattered projectiles, and atomic recoil ions are reported. The studies employed supersonically cooled targets, position imaging detectors, and time-of-flight coincidence techniques; making it possible to simultaneously perform Auger-electron and cold-target recoil-ion momentum spectroscopic (COLTRIMS) measurements. The measurements provide subpartial Auger-electron spectra corresponding to specific final projectile and recoil ion charge states, as well as information on the Q values of the collisions. The measurements provide new insights into the collision dynamics as well as the relaxation pathways of multiply excited states populated during the collisions. [ABSTRACT FROM AUTHOR]

Published
2000

41. Critical Role of Adsorption Equilibria on the Determination of Surface-Enhanced Raman Enhancement

Author

Tripathi, Ashish, Emmons, Erik D., Fountain, Augustus W., Guicheteau, Jason A., Moskovits, Martin, and Christesen, Steven D.

Abstract

Surface-enhanced Raman spectroscopy (SERS) is a useful technique for probing analyte–noble metal interactions and determining thermodynamic properties such as their surface reaction equilibrium constants and binding energies. In this study, we measure the binding equilibrium constants and Gibbs free energy of binding for a series of nitrogen-containing aromatic molecules adsorbed on Klarite substrates. A dual Langmuir dependence of the SERS intensity on concentration was observed for the six species studied, indicating the presence of at least two different binding energies. We relate the measured binding energies to the previously described SERS enhancement value (SEV) and show that the SEV is proportional to the traditional SERS enhancement factor G, with a constant of proportionality that is critically dependent on the adsorption equilibrium constant determined from the dual Langmuir isotherm. We believe the approach described is generally applicable to many SERS substrates, both as a prescriptive approach to determining their relative performance and as a probe of the substrate’s affinity for a target adsorbate.

Published
2015
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42. Ultraviolet Resonance Raman Spectroscopy of Explosivesin Solution and the Solid State.

Author

Emmons, Erik D., Tripathi, Ashish, Guicheteau, Jason A., Fountain, Augustus W., and Christesen, Steven D.

Subjects
*RESONANCE Raman spectroscopy, *EXPLOSIVES, *SOLID-state lasers, *ULTRAVIOLET spectrometry, *WAVELENGTH measurement, *SPECTROMETRY, *LIGHT sources for absorption spectra
Abstract

ResonanceRaman cross sections of common explosives have been measuredby use of excitation wavelengths in the deep-UV from 229 to 262 nm.These measurements were performed both in solution and in the nativesolid state for comparison. While measurements of UV Raman cross sectionsin solution with an internal standard are straightforward and commonlyfound in the literature, measurements on the solid phase are rare.This is due to the difficulty in preparing a solid sample in whichthe molecules of the internal standard and absorbing analyte/explosiveexperience the same laser intensity. This requires producing solidsamples that are mixtures of strongly absorbing explosives and aninternal standard transparent at the UV wavelengths used. For thesolid-state measurements, it is necessary to use nanostructured mixturesof the explosive and the internal standard in order to avoid thisbias due to the strong UV absorption of the explosive. In this studywe used a facile spray-drying technique where the analyte of interestwas codeposited with the nonresonant standard onto an aluminum-coatedmicroscope slide. The generated resonance enhancement profiles andquantitative UV–vis absorption spectra were then used to plotthe relative Raman return as a function of excitation wavelength andparticle size. [ABSTRACT FROM AUTHOR]

Published
2013
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43. Ultraviolet resonance Raman spectroscopy of nitroaromatic compounds for standoff detection applications

Author

Emmons, Erik D., Guicheteau, Jason A., Christesen, Steven D., and Fountain III, Augustus W.

Abstract

Ultraviolet resonance Raman spectroscopy (UVRRS) has been used to examine a variety of different isomers of nitroaromatic molecules. Due to the large cross section enhancements possible, UVRRS has the potential to be a sensitive means for detecting trace quantities of explosives at standoff distances. Since it probes both the electronic and vibrational states of the molecules, it can also be a selective means for differentiating between similar molecules. Resonance Raman spectra will be discussed, along with the different trends that are observed, for the different positional isomers of dinitrobenzene. In addition, spectra for the common explosive 2,4,6-trinitrotoluene will be presented.

Published
2011
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45. Standard method for characterizing SERS substrates

Author

Guicheteau, Jason A., Hankus, Mikella E., Christesen, Steven D., Fountain III, Augustus W., Pellegrino, Paul M., Emmons, Erik D., Tripathi, Ashish, Wilcox, Phillip, and Emge, Darren

Abstract

We present the methodology and results of a standard assessment protocol to evaluate disparate SERS substrates that were developed for the Defense Advanced Research Programs Agency (DARPA) SERS Science and Technology Fundamentals Program. The results presented are a snapshot of a collaborative effort between the US Army Edgewood Chemical Biological Center, and the US Army Research Laboratory-Aldelphi Laboratory Center to develop a quantitative analytical method with spectroscopic figures of merit to unambiguously compare the sensitivity and reproducibility of various SERS substrates submitted by the program participants. We present the design of a common assessment protocol and the definition of a SERS enhancement value (SEV) in order to effectively compare SERS active surfaces.

Published
2012
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46. Proximal and point detection of contaminated surfaces using Raman spectroscopy

Author

Guicheteau, Jason A., Christesen, Steven D., Tripathi, Ashish, Emmons, Erik D., Wilcox, Phillip G., Emge, Darren K., Pardoe, Ian J., and Fountain III, Augustus W.

Abstract

We are actively investigating the use of Raman spectroscopy for proximal standoff detection of chemicals and explosive materials on surfaces. These studies include Raman Chemical Imaging of contaminated fingerprints for forensic attribution and the assessments of commercial handheld or portable Raman instruments operating with near-infrared (IR) as well as ultraviolet (UV) laser excitation specifically developed for on-the-move reconnaissance of chemical contamination. As part of these efforts, we have measured the Raman cross sections of chemical agents, toxic industrial chemicals, and explosives from the UV to NIR. We have also measured and modeled the effect interrogation angle has on the Raman return from droplets on man-made surfaces. Realistic droplet distributions have been modeled and tested against variations in surface scan patterns and laser spot size for determining the optimum scan characteristics for detection of relevant surface contamination.

Published
2011
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47. Foundry-based waveguide-enhanced Raman spectroscopy in the visible.

Author

Tyndall NF, Emmons ED, Pruessner MW, Rabinovich WS, Wilcox PG, Tripathi A, Guicheteau JA, and Stievater TH

Abstract

Waveguide-enhanced Raman spectroscopy (WERS) is an analytical technique frequently employed for chemical and biological sensing. Operation at visible wavelengths to harness the inverse fourth power with excitation wavelength signal scaling of Raman scattering intensity is desirable, to combat the inherent inefficiency of Raman spectroscopy. Until now, WERS demonstrations in the visible have required custom materials and fabrication, resulting in high losses and low yields. In this work, we demonstrate a silicon nitride (SIN) visible WERS platform fabricated in a 300 mm complementary metal-oxide semiconductor (CMOS) foundry. We measure the propagation loss, coupling loss, WERS signal, and background for WERS spirals designed for 532 nm and 633 nm pump wavelengths. We compare these results to the state-of-the-art near-infrared WERS platform at 785 nm. Further, we theoretically validate the relative performance of each of these WERS configurations, and we discuss the optimal WERS configuration at visible wavelengths. We conclude that a configuration optimized for 785 nm pumping provides the greatest signal-to-background ratio in the fingerprint region of the spectrum, and pumping at 633 nm maximizes Stokes signal out to 3000 cm -1 .

Published
2024
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