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Full-Text Articles in Physics

Estimating And Correcting Interference Fringes In Infrared Spectra In Infrared Hyperspectral Imaging, Ghazal Azarfar, Ebrahim Aboualizadeh, Nicholas Walter,, Simona Ratti, Camilla Olivieri, Alessandra Alessandra, Michael Nasse, Achim Kohler, Mario Giordano, Carol Hirschmugl Sep 2018

Estimating And Correcting Interference Fringes In Infrared Spectra In Infrared Hyperspectral Imaging, Ghazal Azarfar, Ebrahim Aboualizadeh, Nicholas Walter,, Simona Ratti, Camilla Olivieri, Alessandra Alessandra, Michael Nasse, Achim Kohler, Mario Giordano, Carol Hirschmugl

Physics Faculty Articles

Short-term acclimation response of individual cells of Thalassiosira weissflogii was monitored by Synchrotron FTIR imaging over the span of 75 minutes. The cells, collected from batch cultures, were maintained in a constant flow of medium, at an irradiance of 120 μmol m−2 s−1 and at 20 °C. Multiple internal reflections due to the micro fluidic channel were modeled, and showed that fringes are additive sinusoids to the pure absorption of the other components of the system. Preprocessing of the hyperspectral cube (x, y, Abs(λ)) included removing spectral fringe using an EMSC approach. Principal component analysis of the ...


Spectroscopy And Formation Of Lanthanum-Hydrocarbon Radicals Formed By C—H And C—C Bond Activation Of 1-Pentene And 2-Pentene, Wenjin Cao, Yuchen Zhang, Silver Nyambo, Dong-Sheng Yang Jul 2018

Spectroscopy And Formation Of Lanthanum-Hydrocarbon Radicals Formed By C—H And C—C Bond Activation Of 1-Pentene And 2-Pentene, Wenjin Cao, Yuchen Zhang, Silver Nyambo, Dong-Sheng Yang

Chemistry Faculty Publications

La atom reactions with 1-pentene and 2-pentene are carried out in a laser-vaporization molecular beam source. The two reactions yield the same metal-hydrocarbon products from the dehydrogenation and carbon–carbon bond cleavage of the pentene molecules. The dehydrogenated species La(C5H8) is the major product, whereas the carbon–carbon bond cleaved species La(C2H2) and La(C3H4) are the minor ones. La(C10H18) is also observed and is presumably formed by La(C5H8) addition to a second pentene molecule. La(C5H8) and ...


Spectroscopy And Formation Of Lanthanum-Hydrocarbon Radicals Formed By Association And Carbon-Carbon Bond Cleavage Of Isoprene, Wenjin Cao, Dilkrushi Hewage, Dong-Sheng Yang May 2018

Spectroscopy And Formation Of Lanthanum-Hydrocarbon Radicals Formed By Association And Carbon-Carbon Bond Cleavage Of Isoprene, Wenjin Cao, Dilkrushi Hewage, Dong-Sheng Yang

Chemistry Faculty Publications

La atom reaction with isoprene is carried out in a laser-vaporization molecular beam source. The reaction yields an adduct as the major product and C—C cleaved and dehydrogenated species as the minor ones. La(C5H8), La(C2H2), and La(C3H4) are characterized with mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemical computations. The MATI spectra of all three species exhibit a strong origin band and several weak vibronic bands corresponding to La-ligand stretch and ligand-based bend excitations. La(C5H8) is a five-membered metallacycle, whereas La(C2 ...


Tip-Enhanced Raman Scattering Of Dna Aptamers For Listeria Monocytogenes, Siyu He, Hongyuan Li, Carmen L. Gomes, Dmitri V. Voronine May 2018

Tip-Enhanced Raman Scattering Of Dna Aptamers For Listeria Monocytogenes, Siyu He, Hongyuan Li, Carmen L. Gomes, Dmitri V. Voronine

Mechanical Engineering Publications

Optical detection and conformational mapping of aptamers are important for improving medical and biosensing technologies and for better understanding of biological processes at the molecular level. The authors investigate the vibrational signals of deoxyribonucleic acid aptamers specific to Listeria monocytogenes immobilized on gold substrates using tip-enhanced Raman scattering (TERS) spectroscopy and nanoscale imaging. The authors compare topographic and nano-optical signals and investigate the fluctuations of the position-dependent TERS spectra. They perform spatial TERS mapping with 3 nm step size and discuss the limitation of the resulting spatial resolution under the ambient conditions. TERS mapping provides information about the chemical composition ...


Lanthanum-Mediated Dehydrogenation Of Butenes: Spectroscopy And Formation Of La(C4H6) Isomers, Wenjin Cao, Dilkrushi Hewage, Dong-Sheng Yang Jan 2018

Lanthanum-Mediated Dehydrogenation Of Butenes: Spectroscopy And Formation Of La(C4H6) Isomers, Wenjin Cao, Dilkrushi Hewage, Dong-Sheng Yang

Chemistry Faculty Publications

La atom reactions with 1-butene, 2-butene, and isobutene are carried out in a laser-vaporization molecular beam source. The three reactions yield the same La-hydrocarbon products from the dehydrogenation and carbon-carbon bond cleavage and coupling of the butenes. The dehydrogenated species La(C4H6) is the major product, which is characterized with mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemical computations. The MATI spectrum of La(C4H6) produced from the La+1-butene reaction exhibits two band systems, whereas the MATI spectra produced from the La+2-butene and isobutene reactions display only a single band system. Each ...


Detection And Characterization Of The Tin Dihydride (Snh2 And Snd2) Molecule In The Gas Phase, Tony C. Smith, Dennis J. Clouthier Jan 2018

Detection And Characterization Of The Tin Dihydride (Snh2 And Snd2) Molecule In The Gas Phase, Tony C. Smith, Dennis J. Clouthier

Chemistry Faculty Publications

The SnH2 and SnD2 molecules have been detected for the first time in the gas phase by laser-induced fluorescence (LIF) and emission spectroscopic techniques through the Ã1B1–X̃1A1 electronic transition. These reactive species were prepared in a pulsed electric discharge jet using (CH3)4Sn or SnH4/SnD4 precursors diluted in high pressure argon. Transitions to the electronic excited state of the jet-cooled molecules were probed with LIF, and the ground state energy levels were measured from single rovibronic level emission spectra. The LIF spectrum of SnD2 afforded ...


Lanthanum-Mediated Dehydrogenation Of 1- And 2-Butynes: Spectroscopy And Formation Of La(C4H4) Isomers, Wenjin Cao, Dilrukshi C. Hewage, Dong-Sheng Yang Aug 2017

Lanthanum-Mediated Dehydrogenation Of 1- And 2-Butynes: Spectroscopy And Formation Of La(C4H4) Isomers, Wenjin Cao, Dilrukshi C. Hewage, Dong-Sheng Yang

Chemistry Faculty Publications

La atom reactions with 1-butyne and 2-butyne are carried out in a laser-vaporization molecular beam source. Both reactions yield the same La-hydrocarbon products from the dehydrogenation and carbon-carbon bond cleavage and coupling of the butynes. The dehydrogenated species La(C4H4) is characterized with mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemical computations. The MATI spectra of La(C4H4) produced from the two reactions exhibit two identical transitions, each consisting of a strong origin band and several vibrational intervals. The two transitions are assigned to the ionization of two isomers: La(η4–CH2 ...


Enhanced Coupling Of Light Into A Turbid Medium Through Microscopic Interface Engineering, Jonathan V. Thompson, Brett H. Hokr, Wihan Kim, Charles W. Ballmann, Brian E. Applegate, Javier Jo, Alexey Yamilov, Hui Cao, Marlan O. Scully, Vladislav V. Yakovlev Jul 2017

Enhanced Coupling Of Light Into A Turbid Medium Through Microscopic Interface Engineering, Jonathan V. Thompson, Brett H. Hokr, Wihan Kim, Charles W. Ballmann, Brian E. Applegate, Javier Jo, Alexey Yamilov, Hui Cao, Marlan O. Scully, Vladislav V. Yakovlev

Physics Faculty Research & Creative Works

There are many optical detection and sensing methods used today that provide powerful ways to diagnose, characterize, and study materials. For example, the measurement of spontaneous Raman scattering allows for remote detection and identification of chemicals. Many other optical techniques provide unique solutions to learn about biological, chemical, and even structural systems. However, when these systems exist in a highly scattering or turbid medium, the optical scattering effects reduce the effectiveness of these methods. In this article, we demonstrate a method to engineer the geometry of the optical interface of a turbid medium, thereby drastically enhancing the coupling efficiency of ...


Quantifying Biochemical Alterations In Brown And Subcutaneous White Adipose Tissues Of Mice Using Fourier Transform Infrared Widefield Imaging, Ebrahim Aboualizadeh, Owen T. Carmichael, Ping He, Diana C. Albarado, Christopher D. Morrison, Carol J. Hirschmugl May 2017

Quantifying Biochemical Alterations In Brown And Subcutaneous White Adipose Tissues Of Mice Using Fourier Transform Infrared Widefield Imaging, Ebrahim Aboualizadeh, Owen T. Carmichael, Ping He, Diana C. Albarado, Christopher D. Morrison, Carol J. Hirschmugl

Physics Faculty Articles

Stimulating increased thermogenic activity in adipose tissue is an important biological target for obesity treatment, and label-free imaging techniques with the potential to quantify stimulation-associated biochemical changes to the adipose tissue are highly sought after. In this study, we used spatially resolved Fourier transform infrared (FTIR) imaging to quantify biochemical changes caused by cold exposure in the brown and subcutaneous white adipose tissues (BAT and s-WAT) of 6 week-old C57BL6 mice exposed to 30°C (N = 5), 24°C (N = 5), and 10°C (N = 5) conditions for 10 days. Fat exposed to colder temperatures demonstrated greater thermogenic activity as ...


Spectroscopy And Formation Of Lanthanum-Hydrocarbon Radicals Formed By C—C Bond Cleavage And Coupling Of Propene, Dilrukshi C. Hewage, Wenjin Cao, Sudesh Kumari, Ruchira Silva, Tao Hong Li, Dong-Sheng Yang May 2017

Spectroscopy And Formation Of Lanthanum-Hydrocarbon Radicals Formed By C—C Bond Cleavage And Coupling Of Propene, Dilrukshi C. Hewage, Wenjin Cao, Sudesh Kumari, Ruchira Silva, Tao Hong Li, Dong-Sheng Yang

Chemistry Faculty Publications

La reaction with propene is carried out in a laser-vaporization molecular beam source. Three La-hydrocarbon radicals are characterized by mass-analyzed threshold ionization (MATI) spectroscopy. One of these radicals is methylenelanthanum [La(CH2)] (Cs), a Schrock-type metal carbene. The other two are a five-membered 1-lanthanacyclopent-3-en [La(CH2CHCHCH2)] (Cs) and a tetrahedron-like trimethylenemethanelanthanum [La(C(CH2)3)] (C3v). Adiabatic ionization energies and metal-ligand stretching and hydrocarbon-based bending frequencies of these species are measured from the MATI spectra, preferred structures and electronic states are identified by comparing the experimental measurements and spectral simulations, and reaction ...


Ultracold Trimer Ion Formation Of Rb And K, Michael Cantara Apr 2016

Ultracold Trimer Ion Formation Of Rb And K, Michael Cantara

University Scholar Projects

The cooling of molecules into the ultracold regime allows for high resolution laser spectroscopy that reveals their complex rotational and vibrational structure. As the temperature is lowered towards absolute zero, the kinetic energy of the particles approaches zero, and therefore the Doppler shift approaches zero. With the Doppler shift negligibly small, spectral resolution is now primarily limited by the natural linewidth of the molecular peaks. Further, ultracold temperatures make possible the production of atoms or molecules that will reside in the lowest few states of the system. The high population in a few select states provides stronger and less congested ...


Observations Of The High Vibrational Levels Of The B′′B̄ 1Σu+ State Of H2, Alexander M. Chartrand, W. Duan, R. C. Ekey, Elizabeth Mccormack Jan 2016

Observations Of The High Vibrational Levels Of The B′′B̄ 1Σu+ State Of H2, Alexander M. Chartrand, W. Duan, R. C. Ekey, Elizabeth Mccormack

Physics Faculty Research and Scholarship

Double-resonance laser spectroscopy via the E F 1Σg+, v'=6, J'=0-2 state was used to probe the high vibrational levels of the B"B-bar 1Σu+ state of molecular hydrogen. Resonantly-enhanced multiphoton ionization spectra were recorded by detecting ion production as a function of energy using a time of flight mass spectrometer. New measurements of energies for the v=51-66 levels for the B"B-bar state of H2 are reported, which, taken with previous results, span the v=46-69 vibrational levels. Results for energy levels are compared to theoretical close-coupled calculations [L. Wolniewicz, T. Orlikowski ...


Identification Of Photocurrents In Topological Insulators, Derek A. Bas, Rodrigo A. Muniz, Sercan Babakiray, David Lederman, J. E. Sipe, Alan D. Bristow Jan 2016

Identification Of Photocurrents In Topological Insulators, Derek A. Bas, Rodrigo A. Muniz, Sercan Babakiray, David Lederman, J. E. Sipe, Alan D. Bristow

Faculty Scholarship

Optical injection and detection of charge currents is an alternative to conventional transport and photoemission measurements, avoiding the necessity of invasive contact that may disturb the system being examined. This is a particular concern for analyzing the surface states of topological insulators. In this work one- and two-color sources of photocurrents are isolated and examined in epitaxial thin films of Bi2Se3. We demonstrate that optical excitation and terahertz detection simultaneously captures one- and two-color photocurrent contributions, which has not been required for other material systems. A method is devised to extract the two components, and in doing so each can ...


Wavelength Dependent Specific Plasmon Resonance Coupling Of Single Silver Nanoparticles With Egfp, Kerry J. Lee, Tao Huang, Prakash D. Nallathamby Jan 2015

Wavelength Dependent Specific Plasmon Resonance Coupling Of Single Silver Nanoparticles With Egfp, Kerry J. Lee, Tao Huang, Prakash D. Nallathamby

Chemistry & Biochemistry Faculty Publications

Noble metal nanoparticles (NPs) possess unique plasmonic properties, enabling them to serve as sub-diffraction light sources and nano-antennae for a wide range of applications. Here we report the specific interaction of single Ag NPs with single EGFP molecules and a high dependence of their interaction upon localized-surface-plasmon-resonance (LSPR) spectra of single Ag NPs and EGFP. The LSPR spectra of single red Ag NPs show a stunning 60 nm blue-shift during their incubation with EGFP, whereas they remain unchanged during their incubation with bovine serum albumin (BSA). Interestingly, the peak wavelengths of the LSPR spectra of green and blue Ag NPs ...


First Measurement Of The Polarization Observable E In The P→ (Ɣ→, Π+) In Reaction Up To 2.25 Gev, S. Strauch, W. J. Briscoe, M. Döring, E. Klempt, V. A. Nikonov, E. Pasyuk, D. Rönchen, A.V. Sarantsev, I. Strakovsky, R. Workman, K. P. Adhikari, D. Adikaram, L. El Fassi Jan 2015

First Measurement Of The Polarization Observable E In The P→ (Ɣ→, Π+) In Reaction Up To 2.25 Gev, S. Strauch, W. J. Briscoe, M. Döring, E. Klempt, V. A. Nikonov, E. Pasyuk, D. Rönchen, A.V. Sarantsev, I. Strakovsky, R. Workman, K. P. Adhikari, D. Adikaram, L. El Fassi

Physics Faculty Publications

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction ɣp→π+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have ...


In-Package Atmospheric Pressure Cold Plasma Treatment Of Cherry Tomatoes, N. Misra, Kevin Keener, Paula Bourke, J Mosnier, Patrick Cullen Mar 2014

In-Package Atmospheric Pressure Cold Plasma Treatment Of Cherry Tomatoes, N. Misra, Kevin Keener, Paula Bourke, J Mosnier, Patrick Cullen

Articles

Cold plasma is increasingly under research for decontamination of foods, especially fresh fruits and vegetables. The effect of cold plasma on food quality, however, remains under researched. This study investigates the effects of cold plasma generated within a sealed package from a dielectric barrier discharge on the physical quality parameters and respiration rates of cherry tomatoes. Respiration rates and weight loss were monitored continuously, while other parameters are reported at the end of storage period. Differences among weight loss, pH and firmness for control and treated cherry tomatoes were insignificant towards the end of storage life. Changes in respiration rates ...


Sensitive And Specific Discrimination Of Pathogenic And Nonpathogenic Escherichia Coli Using Raman Spectroscopy - A Comparison Of Two Multivariate Analysis Techniques, Steven Rehse, Khozima Hamasha, Qassem I. Mohaidat, Russell A. Putnam, Ryan C. Woodman, Sunil Palchaudhuri Jan 2013

Sensitive And Specific Discrimination Of Pathogenic And Nonpathogenic Escherichia Coli Using Raman Spectroscopy - A Comparison Of Two Multivariate Analysis Techniques, Steven Rehse, Khozima Hamasha, Qassem I. Mohaidat, Russell A. Putnam, Ryan C. Woodman, Sunil Palchaudhuri

Physics Publications

The determination of bacterial identity at the strain level is still a complex and time-consuming endeavor. In this study, visible wavelength spontaneous Raman spectroscopy has been used for the discrimination of four closely related Escherichia coli strains: pathogenic enterohemorrhagic E. coli O157:H7 and non-pathogenic E. coli C, E. coli Hfr K-12, and E. coli HF4714. Raman spectra from 600 to 2000 cm-1 were analyzed with two multivariate chemometric techniques, principal component-discriminant function analysis and partial least squares-discriminant analysis, to determine optimal parameters for the discrimination of pathogenic E. coli from the non-pathogenic strains. Spectral preprocessing techniques such as smoothing ...


The Role Of Llnl's Fast Calibration Facility In Diagnosing Nif Fusion Plasmas, Joshua G. Thompson, Carey Scott, Greg V. Brown Aug 2011

The Role Of Llnl's Fast Calibration Facility In Diagnosing Nif Fusion Plasmas, Joshua G. Thompson, Carey Scott, Greg V. Brown

STAR (STEM Teacher and Researcher) Presentations

The Fusion and Astrophysics (FAST) Calibration and Diagnostic Facility uses the original Electron Beam Ion Trap (EBIT-I) to profile x-ray filters that are used in the Dante Soft X-Ray Diagnostic at the National Ignition Facility (NIF). FAST has an advantage over any other facility not only for its high accuracy, but also for its proximity to NIF in the Lawrence Livermore National Laboratory (LLNL). This makes for highly accurate and near-instantaneous filter calibration turnover.

EBIT-I was first constructed to create, trap, and observe static highly charged ions (HCIs) and conduct experimental astrophysics (creating an x-ray spectroscopy catalogue of ions). To ...


Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown Aug 2011

Laboratory Astrophysics: Using Ebit Measurements To Interpret High Resolution Spectra From Celestial Sources, Carey Scott, Joshua Thompson, N. Hell, Greg V. Brown

STAR (STEM Teacher and Researcher) Presentations

Astrophysicists use radiation to investigate the physics controlling a variety of celestial sources, including stellar atmospheres, black holes, and binary systems. By measuring the spectrum of the emitted radiation, astrophysicists can determine a source’s temperature and composition. Accurate atomic data are needed for reliably interpreting these spectra. Here we present an overview of how LLNL’s EBIT facility is used to put the atomic data on sound footing for use by the high energy astrophysics community.


Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler Jan 2011

Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler

Electrical & Computer Engineering Faculty Publications

The time evolution of the ground state wave function of a zero-temperature Bose-Einstein condensate (BEC) gas is well described by the Hamiltonian Gross-Pitaevskii (GP) equation. Using a set of appropriately interleaved unitary collision-stream operators, a qubit lattice gas algorithm is devised, which on taking moments, recovers the Gross-Pitaevskii (GP) equation under diffusion ordering (time scales as length2). Unexpectedly, there is a class of initial states whose Poincaré recurrence time is extremely short and which, as the grid resolution is increased, scales with diffusion ordering (and not as length3). The spectral results of J. Yepez et al. [Phys. Rev ...


Dielectric Properties Of Mixtures Of A Bent-Core And A Calamitic Liquid Crystal, Peter Salamon, Nandor Éber, Agnes Buka, Jim T. Gleeson, Samuel N. Sprunt, Antal Jakli Mar 2010

Dielectric Properties Of Mixtures Of A Bent-Core And A Calamitic Liquid Crystal, Peter Salamon, Nandor Éber, Agnes Buka, Jim T. Gleeson, Samuel N. Sprunt, Antal Jakli

Chemical Physics Publications

Dielectric spectroscopy measurements have been performed on a bent-core nematic liquid crystal and on its binary mixtures with a calamitic nematic. We have detected more dispersions in the bent-core compound than in the calamitic one, including one at an unusually low frequency of a few kilohertz. The dispersions detected in the mixtures have been identified and the spectra have been split into contributions of the constituents. In order to connect the dielectric increment with the molecular dipole moment we have applied a sophisticated conformational calculation not performed before for a large, flexible mesogen molecule with numerous polar groups.


Core-Level Spectroscopy Of The Pd/W(110) Interface: Evidence Of Long-Range Pd-Island—Winteractions At Submonolayer Coverages, D. Mark Riffe, N. D. Shinn, B. Kim, K. J. Kim, T. H. Kang Apr 2009

Core-Level Spectroscopy Of The Pd/W(110) Interface: Evidence Of Long-Range Pd-Island—Winteractions At Submonolayer Coverages, D. Mark Riffe, N. D. Shinn, B. Kim, K. J. Kim, T. H. Kang

All Physics Faculty Publications

We have measured W 4f7/2 core-level photoemission spectra from W(1 1 0) in the presence of Pd overlayers for coverages up to ∼1 pseudomorphic monolayer (ML). At coverages close to 0.05 ML a striking change in the W core-level spectrum is observed, which we interpret as indicating a long-range lateral effect of 2D Pd islands upon the W electronic structure in both the first and second W layers. As the coverage increases the long-range effect weakens and finally vanishes near 0.85 ML. Above this coverage the W spectra are typical for a W-based bimetallic ...


Measurement Of Direct Ƒ0(980) Photoproduction On The Proton, M. Battaglieri, Gerard P. Gilfoyle, Et. Al. Mar 2009

Measurement Of Direct Ƒ0(980) Photoproduction On The Proton, M. Battaglieri, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We report on the results of the first measurement of exclusive ƒ0(980) meson photoproduction on protons for Eγ = 3.0–3.8 GeV and -t = 0.4–1.0 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the π+ π- channel by performing a partial wave analysis of the reaction γ ppπ+π-. Clear evidence of the ƒ0(980) meson was found in the interference between P and S waves at Mπ+π- ∼ 1 GeV. The S ...


Superfluid Turbulence From Quantum Kelvin Wave To Classical Kolmogorov Cascades, Jeffrey Yepez, George Vahala, Linda L. Vahala, Min Soe Jan 2009

Superfluid Turbulence From Quantum Kelvin Wave To Classical Kolmogorov Cascades, Jeffrey Yepez, George Vahala, Linda L. Vahala, Min Soe

Electrical & Computer Engineering Faculty Publications

The main topological feature of a superfluid is a quantum vortex with an identifiable inner and outer radius. A novel unitary quantum lattice gas algorithm is used to simulate quantum turbulence of a Bose-Einstein condensate superfluid described by the Gross-Pitaevskii equation on grids up to 57603. For the first time, an accurate power-law scaling for the quantum Kelvin wave cascade is determined: k-3. The incompressible kinetic energy spectrum exhibits very distinct power-law spectra in 3 ranges of k space: a classical Kolmogorov k-(5/3) spectrum at scales greater than the outer radius of individual quantum vortex cores ...


Spectroscopic Study Of The Dimerisation Process Of Iron Protoporphyrin Ix, K. Dziedzic-Kocurek, Hugh Byrne, A. Swiderski, J. Stanek Jan 2009

Spectroscopic Study Of The Dimerisation Process Of Iron Protoporphyrin Ix, K. Dziedzic-Kocurek, Hugh Byrne, A. Swiderski, J. Stanek

Articles

The commercial protoporphyrin IX, iron-ferriprotoporphyrin IX-chloride and synthesized iron porphyrin μ-oxo-dimers were examined by UV/vis absorption and fluorescence, Fourier transformed infrared spectroscopy, resonance Raman, X-ray absorption, Mössbauer spectroscopy and SQUID. The evidence of Fe-O-Fe antiferromagnetic coupling concluded from SQUID and Mössbauer in the case of samples containing dimerized forms confirmed the presence of the oxo-bridges. In this paper the results of UV/vis, fluorescence, Fourier transform infrared FTIR and Raman spectroscopies are reported and discussed. The study is based on the comparison of the free-base protoporphyrin IX, Fe-PPIX-Cl and the synthesized dimerized specimen. The vibrational modes in two energy ...


Measurement Of Direct Fₒ(980) Photoproduction On The Proton, K. P. Adhikari, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, N. Kalantarians, A. Klein, A.V. Klimenko, S. E. Kuhn, J. Lanchiet, M. R. Niroula, J. Zhang Jan 2009

Measurement Of Direct Fₒ(980) Photoproduction On The Proton, K. P. Adhikari, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, N. Kalantarians, A. Klein, A.V. Klimenko, S. E. Kuhn, J. Lanchiet, M. R. Niroula, J. Zhang

Physics Faculty Publications

We report on the results of the first measurement of exclusive f0(980) meson photoproduction on protons for Eγ = 3.0–3.8  GeV and −t = 0.4–1.0  GeV2 . Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the π+π channel by performing a partial wave analysis of the reaction γp→pπ+π . Clear evidence of the f0(980) meson was found in the interference between P and S waves at M π+π− ∼1  GeV. The S -wave differential ...


Core-Level Spectroscopy Of The Ni/W(110) Interface: Correlation Of W Interfacial Core Levelshifts With First-Layer Ni Phases, D. Mark Riffe, R. T. Franckowiak, N. D. Shinn, B. Kim, K. J. Kim, T. H. Kang Jun 2008

Core-Level Spectroscopy Of The Ni/W(110) Interface: Correlation Of W Interfacial Core Levelshifts With First-Layer Ni Phases, D. Mark Riffe, R. T. Franckowiak, N. D. Shinn, B. Kim, K. J. Kim, T. H. Kang

All Physics Faculty Publications

We have measured W 4f7/2 core-level photoemission spectra from W(1 1 0) in the presence of Ni overlayers, from ∼0.2 to ∼3 monolayers. Interfacial core-level shifts associated with first-layer Ni phases have been identified: −230 ± 15 meV for the 1 × 1 pseudomorphic phase and −70 ± 7 meV for the 7 × 1 close-packed commensurate phase. At higher Ni coverages the interfacial core-level shift is −100 ± 10 meV. These shifts are analyzed using the partial-shift model of Nilsson et al. [Phys. Rev. B 38 (1988) 10357]; the analysis indicates that the difference in binding energies between the 1 ...


A Six-Dimensional H2–H2 Potential Energy Surface For Bound State Spectroscopy, Robert Hinde Jan 2008

A Six-Dimensional H2–H2 Potential Energy Surface For Bound State Spectroscopy, Robert Hinde

Chemistry Publications and Other Works

We present a six-dimensional potential energy surface for the (H2)2 dimer based on coupled-cluster electronic structure calculations employing large atom-centered Gaussian basis sets and a small set of midbond functions at the dimer’s center of mass. The surface is intended to describe accurately the bound and quasibound states of the dimers (H2)2, (D2)2, and H2–D2 that correlate with H2 or D2 monomers in the rovibrational levels (v, j) =(0,0), (0,2), (1,0), and (1,2). We employ a close-coupled approach to compute the energies of these ...


Effects Of Dielectric Relaxation On The Director Dynamics Of Uniaxial Nematic Liquid Crystals, Mingxia Gu, Ye Yin, Sergij V. Shiyanovskii, Oleg Lavrentovich Dec 2007

Effects Of Dielectric Relaxation On The Director Dynamics Of Uniaxial Nematic Liquid Crystals, Mingxia Gu, Ye Yin, Sergij V. Shiyanovskii, Oleg Lavrentovich

Chemical Physics Publications

The dielectric anisotropy of liquid crystals causes director reorientation in an applied electric field and is thus at the heart of electro-optic applications of these materials. The components of the dielectric tensor are frequency dependent. Until recently, this frequency dependence was not accounted for in a description of director dynamics in an electric field. We theoretically derive the reorienting dielectric torque acting on the director, taking into account the entire frequency spectrum of the dielectric tensor. The model allows one to include the effects of multiple relaxations in both parallel and perpendicular components of the dielectric tensor, thus generalizing a ...


Potential Of Vibrational Spectroscopy In The Diagnosis Of Human Tumours., Eoghan O'Faolain Jan 2006

Potential Of Vibrational Spectroscopy In The Diagnosis Of Human Tumours., Eoghan O'Faolain

Doctoral

Just fewer than 20,000 people are annually diagnosed with some form of cancer in Ireland and one in three people are likely to contract some form of cancer by age 74. With the number of cases increasing at an annual rate of 2%, the early detection and treatment of cancer is becoming increasingly important. Both IR and Raman spectroscopy offer the potential for real time, quantitative detection of cancer and even precancer. This study investigates the potential of Raman and Fourier transform infrared, both benchtop and synchrotron spectroscopies for the detection of cervical cancer. The tissue was classified and ...